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Table of Contents

1. Background and Objective -------------------------------------------------------------------------------- 3

2. Plan ------------------------------------------------------------------------------------------------------------- 5

3. Organization ------------------------------------------------------------------------------------------------- 12

4. Research Activities ----------------------------------------------------------------------------------------- 13 4-1. University of Alabama 4-2. University of Delaware 4-3. Max Planck Institute 4-4. Technical University of Darmstadt 4-5. National Institute for Materials Science 4-6. TDK Corporation

5. Appendix ------------------------------------------------------------------------------------------------------ 35 5-1 G8 Consortium Agreement 5-2 The program of the 1st Workshop 5-3 The list of the meetings for the International Organizing Committee

6. Acknowledgements ----------------------------------------------------------------------------------------- 51

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1. Background and Objective

1-1. Background

Permanent magnets (PM) are widely used in numerous applications including electronic devices, actuators, magnetic levitation systems, biomedical devices and motors. State-of-the-art PM are intermetallic compounds consisting of rare-earth (RE) elements and Fe. They derive their exceptional magnetic properties from the combination of the RE sublattice providing the high magnetic anisotropy (K) and the 3d sublattice of Fe giving a large saturation magnetization (Ms) and a high Curie temperature (Tc). To date, the best overall PM involve the ternary compound Nd2Fe14B. Such PM are of increased use in electric motor and generator applications of the energy sector as the coupling means between torque and electricity. The annual increase in NdFeB production has been more than 10% in the past decade and is expected to increase. However, there has been a growing concern that the export of those RE from China, which has about 96% of the world production, will be further restricted, leading to a shortage in supply in other countries. Also, RE extraction processes lead to serious environmental problems. Therefore, the development of high performance RE-free PM is an urgent necessity and of strategic importance for many high-tech applications. A high performance PM requires high coercivity (Hc) and high remanence (Mr), i.e., it must not lose its magnetization even if a large field is applied and it can exert a large field on other objects. A figure of merit for evaluating the strength of PM that takes both factors into account is (BH)max, where B is the magnetic flux and H is the magnetic field. The current maximum value of (BH)max is about 55 MGOe at ambient temperatures in NdFeB type magnets. Among various RE-free alloys and compounds, there are several potential candidates for future PM. Ferrite PM (including Ba- and Sr- ferrites) have been very extensively used for many applications, and represent more than 50% of the PM market. However, the (BH)max values are about 4 MGOe, much lower than that for NdFeB. Recently, nano-crystalline particles of ε-phase Fe2O3 were reported to exhibit Hc of 20kOe and magnetic anisotropy constant (K) of 2x106 erg/cc, but no report of (BH)max has been found in the literature . Other types of PM including Alnico 5 have also been used, but their (BH)max values are about 5 MGOe. There have been recently some interesting developments for high magnetic anisotropy materials. A recent work on L10 FeNi thin films reported high K of 7x106 erg/cc. The stabilization of this phase requires a very rapid cooling process from the high temperature L10 phase. Also α”-Fe16N2 , which has been reported to have high saturation magnetization (Ms) for many years, was recently reported to exhibit a very high K of the same order of magnitude as that for NdFeB. Certainly this is one of the potential candidates for future PM materials, although further work is needed. MnAl and MnBi have also been intensively studied for tape and magneto-optical recording applications. The Mn alloy systems, such as Mn-Al8. Mn-Bi9 and Mn-Ga are known to exhibit high magnetic anisotropy of the order of 107 erg/cc at room temperature and also high Hc (more than 10 kOe). However, the values of (BH)max for those PMs are about 10 ~ 15 MGOe because of low Ms, still much lower than that of NdFeB PM. Nevertheless, the advantage of such Mn-based alloy systems, in addition to attractive magnetic properties, is that Mn and Al are abundant, allowing a cost-effective and sustainable manufacturing process. Until now, very little work has been carried out on developing those systems into PM with high (BH)max. (Table 1 lists the acronyms for the technical terms used.)

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1-2. Objective In view of the above facts, the present consortium will focus on Mn-based alloy systems with Al, Bi and Ga. The objective is to develop high performance and sustainable PM through better understanding of magnetism and structure of Mn-based alloy systems based on an integrated and coherent study of fabrication, characterization, and theory. The final goal is to establish the knowledge towards sustainable manufacturing of PM.

The initial target is to realize Mn-based PM in superlattice thin films and nano-particles with (BH)max of about 25 MGOe and with Hc beyond 15 kOe, which are vitally important for emerging applications such as bio-magnetics magnetic MEMS and electronic appliances (replacing bonded PM). At the second stage, emphasis will be placed on the development from thin films and particles to powders and bulk PM. Also, the development of fabrication processes for production and recycling of the materials will be integrated with the aid of a non-funded industry expert.

The outcome of this project will lead to a path for developing bulk PM with (BH)max, comparable to that for NdFeB. This objective is in accordance with the spirit of the present call, “Replacement of Scarce and Expensive Elements, Critical for Energy Applications”.

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2. Plan

2-1. Overall Plan

The present consortium with the six international organizations will carry out a very systematic and comprehensive research work on Mn-based alloy systems for PM application, consisting of i) Fabrication of thin films, multilayers and particles using various methods, ii) Characterization and analysis for magnetic and structural properties, iii) Theoretical approaches based on micromagnetic calculation and first-principles calculation, and iv) Production and recycling of materials resources.

As mentioned above, there are several key issues to be overcome. The approach to the goal is summarized in Figure 1. The work will be conducted based on the carefully planned timeline, which ensures the close interaction among the partner PIs.

The overall activity will be reviewed by the three committees to achieve the goal. The administration of the consortium will be handled by the MINT Center office at University of Alabama.

2-2. Materials

The Mn atom is known to exhibit a high magnetic moment, though its value is dependent on the distance from, and on the type of, neighboring atoms. Also, depending on the environment around the Mn atom, it is well known that the Mn alloys and intermetallic compounds can be ferromagnetic, anti-ferromagnetic, paramagnetic or ferri-magnetic. The three Mn-based binary alloys (MnAl, MnBi and MnGa) are attractive materials for their magnetic properties and their economic advantages . Depending on the element alloyed with Mn, the alloys can be either magnetically hard (represented by MnAl (τ -phase), MnBi (NiAs-structure) MnGa (δ-phase) or of a ferri-type Mn3Ga). All three alloys, however, are challenging to stabilize with the desired high K, Hc, Ms and crystallographic structures. By investigating systematically the magnetic properties of the Mn-based systems with Al, Bi and Ga, and by controlling the atomistic structures to stabilize the new phases, the potential of Mn-based alloy systems with Al, Bi and Ga for future PM will be demonstrated. The first aim is to understand the interplay between structural, morphological and magnetic properties for those binary alloys. Control of the hard-magnetic properties by grain size and lattice structure will form the basis for the second step of combining the basic building blocks into novel multilayered structures engineered at the atomic level. Those materials in the forms of i) Thin films, ii) Multilayers, and iii) Particles will be fabricated by the sputter-deposition, pulsed laser deposition, chemical synthesis and ball milling techniques.

Towards sustainable manufacturing of permanent magnets

Fabrication MBE, PLD, Sputter-deposition, Chemical synthesis, Ball-milling

CharacterizationStructure, Magnetic, Chemical,

Mechanical property relationshipTheory

First-principles, Multiscale modeling, Large-scale micromagnetics,

Modeling of nanoparticlesProduction and Recycling

Market-driven, Cost-performance, Sustainable materials

25 MGOe at T above 200 C

Mn-AlBiGa

MnAlK = 1 x 10 7erg/cc(BH)max ~10 MGOe

MnBiK = 1 x107erg/cc

(BH)max ~ 15 MGOe

MnGaK = 2 x 107 erg/cc

(BH)max ~ 10 MGOe

Superlattice structure-MBE deposition-Optimization of deposition condition, especially deposition rate and deposition temperature -Selection of buffer layer, substrate materials

Multilayer-Sputter, PLD, MBE deposition-Optimization of deposition condition, especially deposition rate and deposition temperature -Selection of buffer layer, substrate materials

Particles and composites-Chemical synthesis, Ball-milling-Co-reduction method-Selection of precursor molecules, surfactant, carrier liquids

-Narrow size distribution

Approach for High Hc and High Msthrough Fundamental Knowledge –

Atomistic Materials DesignControl of

-interlayer magnetic coupling-hard/soft (core/shell) coupling

-interface structure-microstructure of defects and impurities

-size distribution in particles

Figure 1 Overall plan

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2-3. Fabrication

2-3-1. Superlattice Thin film and Multilayers: (U.A., TUD)

MnAl superlattice thin films and multilayers will be produced primarily by sputter-deposition (LeClair*, Suzuki*) and PLD (A.Gupta*). Also, the MBE method will be employed by Gutfleisch (TUD). The fabrication conditions will be optimized for high Hc and high Tc by a systematic fabrication and characterization plan, in close collaboration throughout the consortium. Using this as feed-back for the sample preparation, we will produce single phase τ -MnAl films with high Hc, Ms, small grains and narrow grain size distribution.

MnBi superlattice thin films and multilayers will be fabricated primarily by sputter-deposition (Hong*, LeClair*, Suzuki*) and PLD (A. Gupta*). The first challenge in the MnBi system is to control the phase instability of the material, as there are two phases present (namely high temperature- and low temperature- phases)9. We will prepare the material on substrates with the same crystal symmetry but the proper amount of lattice constant mismatch. Additional doping with other elements may enable the lattice strain to be maintained over larger film thicknesses. These experiments will require careful control over substrate properties and growth parameters. The preparation effort will be accompanied by XRD (NIMS) and TEM combined with LEAP (NIMS and U.A.). Once the proper phase is stabilized we will seek to optimize the magnetic properties.

MnGa superlattice thin films and multilayers will be sputter-deposited using Ga and Mn effusion cells in a UHV environment (LeClair*). A vacuum chamber with in-situ MOKE, RHEED, LEED and Auger spectroscopy will be dedicated to this task. These films will be deposited on c-Al2O3, GaN(0001) and SiC(111) substrates with suitable buffer and seed layers for epitaxial growth. Thin films of MnGa will also be fabricated under various conditions by PLD so as to optimize for high magnetic anisotropy (A.Gupta*, S.Gupta*).

(Hard/soft) multilayers will be fabricated using sputter deposition (Hong). The magnetic properties of Mn-(Al,Bi,Ga)/(FeCo or FeNi) multilayers will enable us to understand the exchange coupling between the hard and soft films and to investigate the effects of interface roughness and intermixing on the exchange coupling. The magnetic properties of such coupled hard/soft multilayers will be modeled using micromagnetic code. This will provide guidance for the effort to produce nanoparticles of (core/shell) type such as (Mn-(Al,Bi,Ga) with high K) / (FeCo or FeNi with high Ms ) using chemical synthesis.

MnAl-MnBi-MnGa multilayers and Mn-(Al,Bi,Ga) superlattice thin films:

Based on our findings about the individual Mn alloys, we will engineer new hard-magnetic thin films by sputter-deposition, MBE and PLD methods through atomically controlled multilayer design combining the different components (Gutfleisch, U.A.(LeClair*, Hong*, Suzuki*)). This effort will allow us to design and stabilize a new superlattice structure of Mn-(Al,Bi,Ga) thin films, which has not previously been reported in the literature. This effort will require careful analysis of structure, and also of the interface between the different components.

2-3-2. Nano-particles of Mn-(Al,Bi,Ga) by Chemical Synthesis: (U.A.)

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The fabrication of Mn-based nano-particles with a narrow distribution of particle sizes and compositions will be made by a so-called co-reduction method, which has been already proven to be useful for fabricating τ -phase MnAl nanoparticles. (Nikles* and Schad*) The phase behavior of the particles will be systematically studied through thermal heating/cooling analyses. The chemical synthesis work will be aided by computational modeling allowing us to understand the electronic structure of the precursor molecules and the nanoparticles and the mechanism of particle formation (Nikles* and Turner*).

2-3-3. Nano-particles by Surfactant-Assisted Ball Milling: (U.D.)

Mn-based precursor alloys will be prepared by arc-melting. This technique has been proven to be useful for fabricating Sm-Co nanoparticles12. After crushing, the alloys will be subjected to low-energy ball milling in liquid with a rotary mill or to high-energy ball milling in liquid or in argon with a SPEX-8000 mill. Different carrier liquids (toluene, hexane, heptane, ethanol and other organic solvents) and different surfactants (oleic acid, polystearic acid, oleyl amine, trioctylphosphine and others) will be used to establish the optimum milling regimes. The average particle size will be controlled by varying the ball-to-powder ratio, the milling time and surfactant concentration. If necessary, the particle size distribution of the obtained nanoparticles will be narrowed via sedimentation and centrifugal separation. The important aspect of ball-milling the Mn-based metal powders is that the carrier liquid must be non-aqueous. Behavior of the ionic surfactants in non-polar, low-dielectric constant and non-ionizing organic solvents like toluene or benzene differs in many respects from that in aqueous solutions. Oleic acid was found to be a good surfactant for oxide nanoparticles in toluene.

2-3-4. Composites of core/shell type: (U.A., U.D.)

Core(MnAl, MnBi, MnGa)/shell(Fe) nanoparticles (U.A.) will be chemically synthesized by the heterogeneous thermal decomposition of Fe(CO)5 in the presence of MnAl or MnBi or MnGa nanoparticles. Reaction conditions will be identified that give continuous iron shells with control of shell thickness. Fe nanoparticles will be prepared by the thermal decomposition of Fe(CO)5.

Blending/Alignment/Consolidation of Composite Nano-powders (U.D.): In this task, we will use Fe-Co particles smaller than 20 nm and high Hc Mn-based particles smaller than 300 nm. The volume fraction of the soft phase will be varied from 0 to 60%. To avoid agglomeration of the particles, surfactants like oleic acid will be applied to the both powders prior to their blending in an organic solvent. As we expect the Mn-based nanoparticles to be single crystals (and, therefore, magnetically anisotropic), a dc magnetic field will be applied to the wet nanoparticle blend during drying. Sonication will be also used to assure more uniform distribution of the hard and soft nanoparticles in the forming assembly. The effects of both the magnetizing field and sonication on the nanoparticle alignment and mutual arrangement will be closely monitored and analyzed.

The traditional consolidation of anisotropic magnets consists of sintering at 1070 ~ 1200 oC. Such a high temperature cannot be used for nanocomposites, because of inevitable nanoparticle growth and element inter-diffusion. In this project we will use more advanced consolidation techniques including hot compaction (but below the sintering temperature) and shear compaction which will yield near-full density (more than 95%) while preserving the nanostructure.

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Compaction at low temperatures in the range of 500 - 700 oC is commonly applied to nanostructured materials, in particular to magnetically hard RE intermetallic compounds with reported densities over 98%. By limiting the time at the peak temperature one can obtain nearly full density materials without significant coarsening of the nanostructure. Shear compaction is a technique to consolidate powders into bulk samples at room temperature by the application of shear stress to the powder during compression. By aligning the powder in a magnetic field before compressing, high density anisotropic magnets can be obtained.

2-4. Characterization

2-4-1. Magnetic Characterization: (U.A., U.D., NIMS, TUD)

The basic magnetic properties of the samples, such as K, Hc, Ms and Mr will be carefully characterized using a high sensitivity VSM, torque magnetometer, and FMR at U.A., NIMS and Univ. Delaware. The magnetometry will also provide information on magnetic interactions. The magnetic domain structure will be investigated by MFM and SEMPA. Magnetic structural order will be determined by neutron diffraction at national user facilities.

Two types of XMCD measurements will be performed; i) to determine the element-specific magnetic moments of the alloy constituents, which provides information on the exchange interaction in the Mn-alloys, together with modeling of the exchange-dependence of the structure (U.A.-National Synchrotron Light Source (Mankey*)) and ii) to analyze domain patterns and contributions of spin and orbital moments to the spontaneous magnetization in all Mn-based alloys. (MPI (Schütz and Kronmüller)).

The goal of these investigations is to obtain the information to increase Ms by extending the ferromagnetic phase in the Mn-based alloy systems and to control K by enhancing the chemical order or by distorting the lattice through epitaxial strain.

2-4-2. Structural Characterization: (NIMS, U.A., U.D., TUD)

Since coercivity Hc is governed by crystallographic defects and impurities, the structure of PM must be characterized on several scales, i.e. from micro- to nano- and atomic- scales. To achieve high Hc using a hard magnetic phase, it is essential to realize a microstructure in which single-domain sized hard phase grains are embedded in a nonmagnetic phase. To characterize such structures in the experimental Mn-based magnets, HRSEM will be employed for the observation of overall microstructure in three dimensions. Hono and his group at NIMS are experts in this field. Using electron backscattered diffraction in the SEM, they will quantitatively characterize the crystallographic texture in bulk, thin film and particle PM. For the structural and qualitative characterization of interphase and grain boundaries, aberration-corrected scanning TEM will be employed. Since the anisotropy loss at the interfaces influences Hc, atomistic characterization of the surface of the hard phase is necessary. Using Lorenz microscopy, NIMS will observe magnetic domains dynamically under applied magnetic field. The LEAP allows rapid data acquisition of a local chemical composition and pole figure construction for determining three-dimensional structures, such as grain orientations at the atomic scale. Both UA (Thompson*) and NIMS (Hono) have state of the art LEAP tools, so that one can correlate the microstructure and Hc and provide this information as feedback for further microstructural optimization for achieving high Hc.

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In a later stage, high Hc PM will be combined with soft phases to enhance the remanence for achieving usable (BH)max. Then, the nanocomposite microstructure will also be investigated using the above mentioned multi-scale analysis methods. For industrial viability, Hc must persist at high temperatures, so high temperature magnetic measurements will be carried out on the experimental PM using SQUID-VSM at NIMS. It is noted that the equipment available at NIMS for this work includes: i. Laser-assisted 3D atom probe (NIMS-made), ii. FIB/SEM (Zeiss CrossBeam 1540 EsB, Hitachi FB-2100), iii. TEM (Tecnai G2 F30, Titan G2 80-200 S/TEM) and iv. SQUID-VSM (Quantum Design MPMS). TUD will also characterize the structures by HRSEM, HRTEM and various in-situ measurements.

2-4-3. Theory Strategies: (U.A., MPI)

The theoretical component of this consortium is designed to support the experimental efforts in both films and nanoparticles, with closely coupled calculations of electronic structure and micromagnetic behavior.

To maximize (BH)max and Hc in PM, in-depth knowledge of the switching mechanism for magnetization is essential. The two basic types of switching mechanism are nucleation and domain wall de-pinning. The cross-over from a nucleation hardened to a pinning hardened mechanism depends sensitively on the microstructure. If the permanent magnet material contains soft magnetic regions larger than the so-called exchange length, a reversed region will nucleate within this soft magnetic region, leaving a domain wall between the hard and the soft phase. The further details of switching will depend on the nanoscale geometry.

In this project, we will study this complex problem on several different levels. Important insights into basic mechanisms can be gained by analytic and numerical study of simple models, such as planar interfaces or hard-soft composites with only one hard and one soft region. However, to describe real systems quantitatively, it is necessary to do large-scale micromagnetic simulations (C. Mewes* and Kronmüller).

Considering smaller scale calculations first, some of these will be carried out by Kronmüller at MPI using the analytic approach and a finite-difference approach13. In close collaboration with this, an “energy landscape” approach will be used at U.A.14. Visscher has developed a visualization tool that shows a 2D energy landscape, giving the minimum energy at constrained values of the total dipole moment in the easy direction and the quadrupole moment . Unlike analytic approximate methods previously applied to permanent magnet nanostructures, this landscape approach can be applied to layered systems or core/shell nanoparticles of any shape. Another advantage of the landscape method is that the energy barrier can be determined and combined with the temperature dependence of A, Ms, and K to give the temperature dependence of the coercivity, which is of crucial importance for applications.

Complementary to these simplified model calculations we will also carry out larger-scale micromagnetic simulations, both to verify the predicted behavior and to study more complex and realistic structures for comparison with experimental results. Different approaches, including finite-difference as well as finite-element micromagnetic calculations have been used to analyze the effect of exchange coupling between grains and the effect of long range dipole-dipole interactions on remanence and coercivity. However, neglecting the anisotropy of the soft magnetic phase often leads to the unrealistic conclusion that the

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critical dimension of the soft phase for effective exchange coupling only depends on the properties of the hard phase. Recent simulations and experiments have demonstrated that extended micromagnetic models are needed to account for the soft phase effects15. Furthermore, the effects of inter-diffusion and intermixing at interfaces on the inter-phase exchange coupling need to be studied in more detail since this may lead to an enhancement of the energy product. Better physical understanding of the different exchange mechanisms will be obtained through a systematic numerical study of coercivity mechanisms. Here, large-scale micromagnetic simulations will provide detailed insights into the complicated coercivity mechanisms which can change from pinning-like to nucleation-like and depend on the fact that each single domain contains multiple nanoscale grains with different crystalline orientation.

These calculations at U.A. will use the micromagnetic code M3 based on finite differences, developed at U.A. Due to the flexibility of M3, as well as its parallelization capabilities, soft-phase and interfacial effects can readily be incorporated and fundamental questions regarding the dominant coercivity mechanism in the proposed materials will be studied. The numerical investigations will be accompanied by detailed experimental work including structural characterization and magnetic characterization.

The micromagnetic investigations of the soft-phase and interfacial effects will be carried out in close collaboration by U.A. and MPI. The project will not only benefit from their expertise in large scale micromagnetic modeling, but also from their commercial micromagnetic code – this is based on finite elements, which can describe complex geometry more easily than finite difference codes. Since all micromagnetic calculations require a knowledge of material constants such as K, A, and Ms, the simulations will also benefit from the characterization work mentioned above (Sec. 9.2d), especially the XMCD work of Prof. Schütz’ group at MPI.

The electronic structure work will be carried out at U.A. (Mryasov*), focusing on material-specific models for fundamental magnetic properties (Ms, A, K) as a function of temperature needed for micromagnetic simulations. This will involve extensions of traditional density functional theory (DFT-LDA based) to account for many-electron contributions to the orbital dependence of effective electron potentials16. We will study interface and bulk exchange interactions and critical temperatures for prospective RE-free permanent magnets, to support the search for optimum composition, alloy additions, and conditions (strain, stress). In combination with micromagnetic theory, this will allow us to maximize (BH)max by exploring Mn-based materials and their nanostructures.

2-5. Application and Production: (TDK,TUD)

Since high productivity and superior cost-performance are key to the success of the commercialization of PM, most of the commercial PM have been produced by powder processes, such as fine milling, molding and sintering. Melt quench, mechanical alloying, and solid state reaction such as the reduction-diffusion method may also be other candidates to apply for Mn-based PM. Furthermore, gas phase synthesis or liquid phase reaction can be candidates for fabricating powders for PM.

Mn-based alloy magnets may be used for applications similar to those of the sintered or bonded NdFeB magnets, such as motors, actuators, generators and sensors for cars, household appliances, hard disk drives, wind generators, and so on. TDK will search market demands and will assign the possible applications suitable for Mn-based PM. Thin film PM are expected to be utilized for magnetic MEMS such

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as micro-actuators and high frequency devices in the future17,18. Nano-particle PM have been used in the bio-medical area19. TDK will collaborate with the consortium members on the production processes using the methods mentioned above, once the chemical compositions, microstructures, magnetic and other properties are optimized by the present consortium.

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3. Organization

PI: Professor Takao Suzuki (Univ. Alabama, USA)

Oversight of the ProgramFabrication, Characterization and

Theory

Professor Helmut Kronmuller

(Max-Planck Institute, Germany)

Basic Physics of (BH)max.

Dr. Kiyoyuki Masuzawa(TDK ,Japan)

Manufacturing of Rare-earth Free Permanent

MagnetsAnd their Applications

PPI: Dr. Oliver Gutfleisch

(Technical University of Darmstadt, Germany)

Characterization , Application and Recycling

of Raw Materials

PPI: Professor George Hadjipanayis

(University of Delaware, USA)

Optimization of (BH)max in Nano-composites of Hard

Magnets

PPI: Professor Kazuhiro Hono

(National Institute for Materials Science, Japan)

Characterization and Basic Physics

Replacement of scarce and expensive elements for

energy application

Rare-earth Free Permanent Magnets for Next Generations

PPI: Dr. Helmut Kronmuller

(Max-Planck Institute, Germany)

Basic Physics of (BH)max.

PPI: Dr. Shin-Ichiro Itoh

(TDK ,Japan)Manufacturing of Rare-earth Free Permanent

MagnetsAnd their Applications

Figure 2 Organization – PI and PPI

- MINT, Univ. Alabama, - University of Delaware- Max-Planck Institute- National Institute for

Materials Science-Technical University of

DarmstadtTDK

Rare-earth Free Magnets

Consortium Newsletter

IOC: International Oversight CommitteeCAC: Consortium Advisory Committee

MCC: MINT Consortium Committee

IOC

MCC

CAC

Consortium Administration Office(MINT Office, U.Alabama)

Consortium Web.site

Consortium Workshop

Knowledge Transfer to Public(Journals, Conferences, Web.,)

Education/Outreach

Mutual Site Visit

Figure 3 Organization - Committees and Activities

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4. Research Activities

4-1. University of Alabama PI: Takao Suzuki, Co-PI: A.Gupta, S.Gupta, Y.K.Hong, G.Mankey, C.Mewes, T.Mewes, O.Mryasov, D.Nikles, R.Shade, G.Thompson , H.Turner and P.Visscher (consultant)

4-1-1. Magnetism and Structure in Mn-X Thin Films (X=Bi,Rh,Al,Ga): (Suzuki, LeClair, Gary, Hong, T.Mewes, A.Gupta, Shade, Thompson, Mryasov, Hozumi (PD), Chaturvedi (PD) and Zhao (PhD student)) A systematic work of MnBi, MnRh and MnAl multilayers for achieving high magnetic anisotropy (K) and high coercivity (Hc) has been carried out in conjunction with microstructural study. Samples were fabricated onto various substrates such as silica-glass, Si, Al2O3 by sputter deposition technique in vacuum better than 10-8 Torr, for which fabrication conditions were optimized for high K and high Hc values.

MnBi:

- MnBi thin films with high magnetic anisotropy (>107erg/cc ) and high coercivity (>15kOe) at room temperature have been successfully fabricated under optimized annealing conditions for multilayers of (Bi/Mn)xN. (Figure 1) - The MnBi films thus fabricated exhibit the temperature dependence of Hc, showing the increase of Hc with T up to about 150C. - X-ray diffraction analysis indicates that the MnBi films are of low temperature phase (LTP) and well oriented along the c-axis perpendicular to film plane for the silica-glass. (Figure 2) - High resolution electron microscopic study reveals that the LTP grains of about 50 – 200nm in size are isolated by Bi grains of nearly the same size. Since those grains are smaller than that for a critical size for a single domain configuration, it is believed that high coercivity of LTP MnBi resulted from the single domain behavior. (Figure 3) - The magnetic interaction among the LTP grains was examined for the film with N = 10 by using the so-called M measurements. Figure 4 shows the M { = 2Mr(H) -1 + Md(H) } curve in the out-of-plane measurement, where Mr(H) and Md(H) are isothermal remanence (IRM) and dc-demagnetization remanence (DCD) curves (normalized to saturation magnetization), respectively. Measurements of Mr(H) and Md(H) were conducted starting from ac-demagnetized and saturation magnetization state, respectively. (Fig.4) The M curve exhibits a negative peak, indicating magnetostatic interaction between the LTP is a dominant over an exchange nteraction. This result is consistent with the observation by TEM and EDS, as the LTP grains are physically separated by Bi grains, roughly 20 – 50 nm apart. - Ferromagnetic resonance study is in progress to understand the damping mechanism. - Mechanism of anomalous temperature dependence of magnetic anisotropy in LTP MnBi has been theoretically studied. The strong dependence of magnetic anisotropy on lattice parameters (c and a) of LTP MnBi was found. This calculation suggests that the contribution of magnetostriction to the magnetic anisotropy K is not significant. and thus the magnetic anisotropy mechanism is dominated by electron-lattice coupling.

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Figure 1 M-H loops for (Bi/Mn)xN multilayers annealed at 550C for 30min.

Figure 2 XRD patterns for (Bi/Mn)xN multilayers annealed at 550C for 30min.

Figure 3 (a) High resolution TEM image of a cross-section (b) STEM image and EDS for the sample with N=10. The work was carried out by the team of NIMS led by Dr. Hono.

Figure 4 The ΔM curve for the sample with N=10. Here, DCD and IRM are the isothermal remanence magnetization and the dc demagnetization remanence, respectively. The ΔM curve implies that the magneto-static interaction among the LTP grains is dominant over an exchange interaction.

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MnRh:

Ferromanetic MnRh thin films (equiatomic composition) were successfully fabricated by sputter deposition, whereas the bulk MnRh of similar compositions exhibits antiferro magnetic at room temperature. - Those films exhibit Hc around 500 Oe at room temperature. - The films exhibit a presence of high magnetic anisotropy component evidenced by the gradual increase of magnetization with field at high fields - The temperature dependence of magnetization shows that there is a very large hysteresis between heating and cooling processes. - This hysteresis is likely to be due to the transformation between ferromagnetic and antiferromagnetic states, but further study is necessary. - An XMCD study of MnRh thin films is in progress to identify the magnetism of those MnRh samples. MnAl: - MnAl thin films with high Hc (> 3kOe) were successfully fabricated onto various substrates described above by sputter-deposition. - Those films are found to be of the τ-phase. - Work is in progress for further optimization of film-structure to obtain Hc larger than 10 kOe. MnGa: - Preparation of fabrication of MnGa multilayer thin films by both sputter-deposition and laser-pulse deposition is under way.

4-1-2. Fabrication and Characterization of Mn-X Nano-particles: (Nikles, Thompson, Turner and Zhao (PhD student))

- MnBi nanoparticles were successfully fabricated by chemical synthesis method. The simultaneous thermal decomposition of dimanganese decacarbonyl and chemical reduction of bismuth chloride gave a mixture of large (~100 nm) Bi particles and small (~10 nm) MnBi particles. - Considerable work on the synthesis of MnAl nanoparticles pursued two routes, 1) simultaneous reduction of AlCl3 and MnCl2, or 2) formation of Al nuclei, followed by reduction of MnCl2 in the presence of the Al particles. Both Al(III) and Mn(II) were very difficult to reduce and this had made the synthesis of MnAl particles very difficult to reproduce. During this project, a convenient method of preparing Al nanoparticles by the thermal decomposition of triisobutylaluminum was foud. A manuscript on this new synthesis has been submitted for publication to the Journal of Nanoparticle Research. - Simulations of Chemical and structural ordering within AlMn nanoparticles are in progress to identify the energetics of structural and chemical transformations within the nanoparticles as a function of the temperature and other environmental effects.

4-1-3. Fabrication and Characterization of Spring Magnet Thin Films; FePtB/FeB: (S.Gupta)

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- The multilayer samples of (FeB/Pt) were successfully fabricated onto Si substrates by sputter-deposition. By tuning each layer thickness and annealing condition, coercivity as high as 8kOe was obtained. An estimated (BH)max for [FePtB/FeB] is about 5 MGOe at room temperature. - A further work is in progress for higher (BH)max through optimizing film-structure.

4-1-4. Micromagnetic Simulation of (BH)max: (C. Mewes and Visscher (Consultant))

- Micromagnetic simulations have been carried out for hard-soft composite systems, especially multilayers and nanoparticles. All calculations were carried out within the code M3, developed in the group of T. Mewes and C. Mewes, or within the SpinFlow3D software package. In the simulation, magnetic anisotropy of soft magnetic phase are taken into account. Also, misalignment of an external field is considered. The values of (BH)max as a function of exchange coupling (J) between soft and hard layers shows a significant enhancement of (BH)max for J above 10-2(J/m2). - A new micromagnetic approach to understanding the behavior of permanent magnets based on an energy landscape picture is in progress. This method is applied to more complicated systems such as core-shell particles, and will be implemented for constructing shapes by arbitrarily nested intersections and unions of ellipsoids and polyhedral, so that complex structures can be modeled accurately. 4-1-5. Publications: - L,Zhang, G.Thompson and D.Nikles: "Synthesis of aluminum nanoparticles by decomposition of triisobuthylaluminum" submitted to J. Nanoparticle Research. - Lei Zhang. PhD Thesis “On the Chemical Synthesis of Manganese-based High Magnetocrystalline

Anisotropy Energy Density Magnetic Particles” (2013). University of Alabama. 4-1-6. Presentations: - T.Suzuki, T.Hozumi, P.LeClair, C.Mewes and G.Mankey: “Rare-earth free permanent magnets” The 3rd International Symposium on Advanced Magnetic Materials and Applications (July 21-25, 2013, Taichung, Taiwan (Invited). - L. Zhang, G. B. Thompson and D. E. Nikles: “Synthesis of aluminum nanoparticles” American Chemical Society Annual Meeting (April 2013, New Orleans). - C. Mewes, T.Mewes " Micromagnetic Calculations for Hard Magnets" to be presented at Magnetism and Magnetic Materials Conference (Denver, Nov., 2013). - T. Hozumi, P. LeClair, G. Mankey, C. Mewes, H. Sepheri-Amin, K. Hono, and T. Suzuki: "Magnetic and Structural Properties of MnBi Thin Films" to be presented at Magnetism and Magnetic Materials Conference (Denver, Nov.,2013). 4-1-7. Post-doctoral fellows and students participations: Toshiya Hozumi Postdoctoral Anurag Chaturvedi Postdoctoral Siqian Zhao Lei Zhang

Graduate Student (research assistant) Graduate Student (research assistant)

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Sean Perry Research Experience for Undergraduates (REU) Sam Schwarm Research Experience for Undergraduates (REU) Eshan King High School Student 4-1-8. Dissemination: - MINT Website: http://mint.ua.edu - G8 News Letter (No.1) - NSF report (2012-2013) submitted and approved (September, 2013).

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4-2. University of Delaware PPI: Professor George Hadjipanayis

The aim of the work is to synthesize rare-earth-free hard magnetic nanoparticles, especially MnBi, with high coercivity (Hc) and magnetization using the mechanochemical synthesis process and investigate the effect of process conditions such as amount of CaO dispersant, starting Bi/Mn ratio and heat treatment temperatures on the phase formation, particle size and magnetic properties. It is to be noted that previously there were no reports on the synthesis of MnBi nanoparticles. In this work, we report, for the first time, the synthesis of MnBi nanoparticles by mechanochemical process with size in the range 100-300 nm having high coercivity in the range of 12-18 kOe.

Experiments

The precursors used in these experiments were powders of Bi2O3, Mn, CaO and granules of Ca. Reactant powders were sealed in a hardened steel vial under Ar atmosphere and subjected to high energy ball milling (HEBM). HEBM was performed with SPEX-8000 for 4 h with balls to powder ratio of 10:1. The powder was handled inside the Ar-filled glove box to prevent oxidation. Different amount of extra CaO (0-45wt.%) was added to the reactants prior to milling in order to separate the product particles. Two step annealing was performed on the as-milled samples. In the first step, powders were annealed in the temperature range 800–1200 °C for 5-10 min in quartz tube under a vacuum and quenched to room temperature in air. Second step annealing was performed at 300°C for 15 h. To remove the CaO, multi-step washing protocol was employed, includes washing with de-ionized, deoxygenated water and a deoxygenated 4 vol% acetic acid aqueous solution.

The effect of variation of Bi/Mn ratio, Ca/O ratio, amount of excess dispersant CaO, and annealing temperatures on the phase formation, magnetic properties and particle size were investigated extensively. A brief summary of the results is given below. All the results are reported on washed powders.

Results and discussion

a) Effect of amount of excess

dispersant CaO

The amount of excess CaO was varied from 15-45% keeping constant a Ca/O ratio of 1.18 (this ratio was also optimized) and Bi/Mn ratio of 0.3. Annealing was done at 800°C /10 min followed by a long term annealing of powders at 300°C for 15 h. Figure 1 shows the XRD patterns of the washed MnBi nanoparticles prepared with different excess CaO. The powders consist of MnBi LTP and Bi phases. With increase of excess CaO, a lower volume

BiMnBi

2θ (deg.)

Inte

nsity

(a.u

.)

CaO=45%

CaO=40%

CaO=35%

CaO=30%

25 30 35 40 45 50 55

CaO=20%

CaO=15%

Fig. 1. XRD patterns of the washed MnBi nanoparticles prepared with different excess CaO

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fraction of MnBi phase was formed due to the suppression of diffusion between Bi and Mn. The corresponding half hysteresis loops are shown in Fig 2. The Hc and Ms values extracted from Fig. 2 are plotted in Fig.3 as a function of CaO amount. As seen from Fig. 3, Ms decreases with increase of CaO. While the Hc shows increasing trend up to 40% and thereafter decreases. The obtained Hc and Ms are in the range of 11-18 kOe and 13-25 emu/g, respectively. SEM images of the particles for different CaO are shown in Fig. 4. It can be seen that more separated particles formed for higher dispersant (CaO) and the particle are in the size range 100-300 nm.

Fig. 3. Variation of Ms and Hc with different excess CaO

-30000 -20000 -10000 0 10000 20000 30000-30

-20

-10

0

10

20

30

CaO= 40% CaO= 45%

CaO= 30%

CaO= 15% CaO= 20% M(

emu/g

)

Magnetic Field (Oe)

CaO= 35%

15 20 25 30 35 40 4510

12

14

16

18

20

22

24

26

Hc(kO

e)

Ms(e

mu/g)

CaO (%)

Ms Hc

10

12

14

16

18

Fig. 2. Half Hysteresis loops of powders processed with different excess CaO

Fig. 4 SEM images of the MnBi nanoparticles prepared with different excess CaO

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Fig. 5. XRD patterns of the washed MnBi nanoparticles prepared with different Bi/Mn ratios

b) Effect of variation of Bi/Mn ratio

The ratio of Bi/Mn in the precursor powders was varied from 0.2 to 1.08 keeping a constant Ca/O ratio of 1.18 and an excess dispersant CaO amount of 30%. Annealing was done at 800°C /5 min followed by a long term annealing of powders at 300°C for 15 h. Figure 5 shows the XRD patterns of the washed MnBi nanoparticles prepared with different Bi/Mn ratio. The sample with Bi/Mn ratio of 0.3 shows a higher volume fraction of MnBi phase as compared to the others. The half hysteresis loops of the samples are displayed in Fig. 6 for comparison. Nearly rectangular demagnetization curve with higher magnetization has been observed for the sample prepared with Bi/Mn ratio of 0.3. The Hc and Ms values extracted from Fig. 6 are plotted in Fig. 7 as a function of Bi/Mn ratio for better clarity. The Ms shows a peak at Bi/Mn ratio of 0.3 while the Hc shows a peak value at a Bi/Mn ratio of 0.81. The obtained Hc and Ms values are in the range 16-19 kOe and 4-18 emu/g, respectively.

Fig. 6. Half Hysteresis loops of powders processed with different Bi/Mn ratios Fig. 7. Variation of Ms and Hc with different

Bi/Mn ratios

25 30 35 40 45 50 55

Mn

Bi/Mn = 0.2

Bi/Mn = 0.3

Bi/Mn = 0.4Bi

MnBi

Inte

nsity

(a.u

.)

2θ (deg.)

20

c) Effect of of annealing temperature

For this study, we have selected the sample prepared with Bi/Mn ratio of 0.3, CaO amount of 30% and Ca/O ratio of 1.18 because it showed higher Ms and Hc values. The first annealing step was performed at different temperatures, i.e. 800°C /5 m, 900°C /5 m and 1200°C /3 m, then the second annealing step was done at 300°C for 15 h. Figure 8 shows the XRD patterns of the MnBi nanoparticles annealed at different temperatures. With increase of annealing temperature, the volume fraction of the MnBi phase increases and this increase is also reflected in the magnetization curves (Fig. 9) which clearly show higher Ms values. The effect of annealing temperature on particle size is shown in Fig. 10. As seen from SEM images, the average particle size increases from 200 nm to 2 µm as the annealing temperature increases from 800°C to 1200°C.

Fig. 8. XRD patterns of MnBi particles annealed at different temperatures.

Fig. 9. Half Hysteresis loops of powders annealed at different temperatures.

Bi MnBi

25 30 35 40 45 50 55

800C/5 min

1200C/3 min

900C/5 min

2θ(deg.)

Inte

nsity

(a.u

.)

Fig. 10. SEM images of the MnBi particles prepared at different annealing temperatures.

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Future Work

We will continue our studies to synthesize nanoparticles with a higher volume fraction of the LTP MnBi phase and also to understand the formation of these nanoparticles at each stage of processing by performing careful microstructural studies.

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4-3. Max Planck Institute for Intelligent Systems (Formally MPI for Metals Research) PPI: Helmut Kronmüller, Co-PI: Dr. Yu-Chun Chen, Dr. Eberhard Goering and Dr. Gisela Schütz

Micromagnetic analysis of the temperature dependence on the coercive field of MnBi nanomagnets.

Yu-Chun Chen, Eberhard Goering, Gisela Schütz, Helmut Kronmüller

Abstract

In the first year of this G8 project, the temperature dependent XMCD measurements of bulk MnBi magnets have been accomplished in ANKA synchrotron center (Karlsruhe Germany). The preliminary data analysis presents that the spin and orbital moments change significantly with measuring temperature. The interesting finding is that the hysteresis curves of isotropic and anisotropic bulk MnBi samples obtained from XMCD signals show similar feature in contrast with corresponding SQUID results. This unexpected evidence maybe indicates that the texture of MnBi magnet plays a crucial role in macroscopic behavior. While at the atomic scale the mechanism for the increase in anisotropy at high temperature remains theoretically unresolved, the temperature dependent coercive field can be explained well with Kronmüller’s model. Further XMCD measurements and precise data analysis are required and will be done in several months.

Since September in 2012, temperature dependent XMCD measurements of bulk MnBi magnets have been done at WERA beamline of ANKA synchrotron center. The specimens include three samples ― two from USA (Prof. Hadjiapanayis’s group) and one prepared by MPI (Prof. Schütz’s group). In order to investigate the microscopic magnetic properties of MnBi magnets, Prof. Hadjiapanayis provides us both isotropic and anisotropic samples. The former sample was prepared only by arc melting under pure argon atmosphere and then annealed at 300 °C for 24 hours. Therefore, it is found that some starting materials, Mn and Bi metal, still exist within whole texture based on XRD and SEM analysis. To obtain highly anisotropic MnBi magnets, the annealed ingot was further treated with ball milling and subsequently pressed via hot compaction at 260 °C. Due to this post treatment, the magnetization of MnBi specimen turns into anisotropic behavior and presents remarkable change in unusual positive temperature coefficient of the coercivity. In the case of the MPI sample, the only difference is that bulk magnet was compacted with Spark plasma sintering technology. The SQUID data of these three samples are shown in Figure 1. Although the volume sensitive SQUID hysteresis loops show strong difference between isotropic and anisotropic specimens, the elemental specific XMCD hysteresis loops exhibit nearly identical behavior as seen in Figure 2.

According to this unexpected finding, a detailed analysis of the microscopic magnetic properties of MnBi compound is clearly indispensible. Therefore we have measured XMCD spectra of MPI sample at three different temperatures (78 K, 300 K, 380 K respectively). The evaluated magnetic moments are summarized in Table 1 based on sum rules.

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Figure 1. Temperature dependent SQUID results of (a) USA-isotropic, (b) USA-anisotropic (hot compaction), and (c) MPI-anisotropic (SPS) MnBi magnets. It is noted that phase transition occurs above 650 °C.

Figure 2. Hysteresis loops of (a) isotropic and (b) anisotropic MnBi magnets obtain from XMCD spectra (Mn L3 edge) measured at 300 K.

Table I. Summary of magnetic moments of MPI sample obtained from temperature dependent XMCD measurements. The values in square brackets present the magnetic moments per formula unit evaluated from corresponding SQUID data.

Measuring temperature ms[𝜇𝜇𝐵𝐵] ml[𝜇𝜇𝐵𝐵] mtot[𝜇𝜇𝐵𝐵] 78 K 1.41 0.14 1.55

300 K 1.32 0.33 1.65

[2.41] 380 K 1.87 0.36 2.23

[2.24]

It is noted that all of these values are preliminary results. Nevertheless, the change in magnetic moments is indeed apparent. Therefore we already performed recently in Aug 2013 further high quality XMCD investigations, which are under analysis.

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Besides experimental work, the theoretical explanation on this unusual magnetic property of MnBi was carried out by Prof. Kronmüller. Based on his nucleation mechanism, the analysis of the temperature dependence of the coercive field can be described by the well-known equation1

𝐻𝐻𝑐𝑐 = 2𝐾𝐾1Js𝛼𝛼𝑘𝑘 − 𝑁𝑁𝑒𝑒𝑒𝑒𝑒𝑒𝑀𝑀𝑠𝑠 (1)

, where 𝛼𝛼𝑘𝑘 and 𝑁𝑁𝑒𝑒𝑒𝑒𝑒𝑒 denote microstructural parameters taking care of the deteriorations of the anisotropy constants at grain surfaces and of the increased stray fields at corners and edges.

The parameters 𝛼𝛼𝑘𝑘 and 𝑁𝑁𝑒𝑒𝑒𝑒𝑒𝑒 are determined by plotting

𝜇𝜇0𝐻𝐻𝑐𝑐/J𝑠𝑠 vs. 2𝐾𝐾/𝑀𝑀𝑠𝑠J𝑠𝑠 (2)

in dependence of temperature. Here, the left side of the equation corresponds to the experimental results for 𝐻𝐻𝑐𝑐 and the right side presents the theoretical deduction where, of course, K1 again has to be determined by measurements. To verify this relationship we fit the results originally from our sample and those published by Yang et al2.

As shown in Figure 3, the plots lead to a linear behavior for all of three data series. After linear fitting, our result gives, based on eq.(2), a straight line with slope 𝛼𝛼𝑘𝑘 =0.3 (0.3) and an intersection with the ordinate at 𝑁𝑁𝑒𝑒𝑒𝑒𝑒𝑒 = 0.75 (1.4).

Figure. 3

Using previous theoretical results derived for a deteriorated surface region, 𝛼𝛼𝑘𝑘 gives information about the width of the region of reduced magnetocrystalline anisotropy given by

𝑟𝑟0 = �1−𝛼𝛼𝑘𝑘𝜋𝜋𝛼𝛼𝑘𝑘

𝛿𝛿𝐵𝐵 (3)

,where 𝛿𝛿𝐵𝐵 = 𝜋𝜋�𝐴𝐴/𝐾𝐾1 meaning the domain wall width. With 𝐴𝐴 = 8 × 10−12 J/m and 𝐾𝐾1 = 1.2 ×106 J/m3 determined by Guo et al3, this gives 𝛿𝛿𝐵𝐵 = 8.11 nm. From eq. (3), we obtain a deteriorated width of 𝑟𝑟0 ≅ 7.2 nm.

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The linear relation found from the plot according to eq.(1) clearly proves that the hardening mechanism in nanocrystalline MnBi permanent magnets corresponds to the nucleation mechanism.

Reference

1. H. Kronmüller, Phys. Status Solidi b 144 385 1987 2. J. B. Yang, Y. B. Yang, X. G. Chen, X. B. Ma, J. Z. Han, Y. C. Yang, S. Guo, A. R. Yan, Q. Z. Huang, M. M.

Wu, and D. F. Chen, Appl. Phys. Lett. 99, 082505 2011 3. X. Guo, X. Chen, Z. Altounian, and J. O. Ström-Olsen, Phys. Rev. B 46 14578 1992

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4-4. Technical University of Darmstadt PPI: Oliver Gutfleisch

Developing a new generation of high-performance (FeCo)xB +MnAl permanent magnets: Stage 1 – optimization the (FeCo)2B semi-hard phase

K.P. Skokov,a M.D. Kuz’min,a H. Jiang,a I. Radulov,a and O. Gutfleischa,b a Institut für Materialwissenschaft, Technische Universität Darmstadt, 64287 Darmstadt, Germany b Fraunhofer IWKS, Materials Recycling and Resource Strategy, 63457 Hanau, Germany

As far as intrinsic magnetic properties are concerned, a prospective new permanent magnet material must satisfy certain necessary conditions. It should possess (i) a high Curie temperature, (ii) a large saturation magnetization and (iii) a strong magnetic anisotropy of the easy-axis type. It is the latter requirement that presents the real challenge, 3d materials fulfilling the former two criteria are long known. This is, e.g., permendur, Fe0.65Co0.35, with TC = 1250 K and Js = 2.5 T. One can paraphrase that making a rare-earth-free permanent magnet narrows down to finding a 3d material with a sufficiently strong easy-axis anisotropy.

In non-rare-earth containing magnetic materials with high Fe concentration the magnetocrystalline anisotropy is usually very weak, and alloys with K1≈0.5 MJ/m3 (called ‘semi-hard’ materials [1]) are a rare exception. They still cannot be judged as adequate materials for PM-production, but they can be very useful as a matrix phase in composite magnets, where the hard RE-free magnetic phase (e.g. Mn-Al or Mn-Bi) is associated with the semi-hard Fe-rich magnetic matrix phase.

The objective is to make a composite permanent-magnet material, where the hard phase would be based on Mn-Al. At the first stage of the project it had to be decided on the composition of the semi-hard phase. According to Skomski’s theory [1] the semi-hard phase should have a magnetization significantly higher than that of the hard phase, and a significant uniaxial anisotropy as well. So, for the semi-hard phase we chose the (Fe1-xCox)2B compounds early investigated by Iga [2].

Fig. 1 Magnetization curves of (Fe0.7Co0.3)2B for two orientations of applied magnetic field and six different temperatures.

27

We grew several single crystals of (Fe1-xCox)2B with different Co contents x and measured their intrinsic magnetic properties. It was necessary to optimize x because both Fe2B and Co2B are easy-plane compounds and only the mixed alloys have the sought easy-axis anisotropy. We found that the anisotropy constant K1 is a maximum at x=0.3 and so the compound (Fe0.7Co0.3)2B was finally selected to be the semi-hard phase. It has a high Curie point, TC=937 K, and a large spontaneous polarization, Js=1.42 T at 10 K and Js=1.31 T at room temperature. This is nearly twice as high as that of in the hard phase Mn-Al (Js=0.73 T) at room temperature. At the same time has an appreciable easy-axis anisotropy: K1 =0.51 MJ/m3 at 10 K and K1=0.42 MJ/m3 at room temperature (see figures 1-3). This is about one-half of the anisotropy of Mn-Al (1 MJ/m3 at room temperature). Thus, (Fe0.7Co0.3)2B fulfills all the criteria of Skomski’s theory [1] for the semi-hard phase in a composite permanent magnet.

At the same time as the properties of the semi-hard phase were being investigated, we were working on the synthesis of the Mn-Al phase. Mn53Al47 alloys were prepared by induction melting under argon atmosphere. The ingots were annealed at 1150 °C for 24 h followed by water quenching to retain the ε phase. The quenched bulk samples were annealed at a temperature of 500 °C for 2 days, to produce the ferromagnetic L10 τ phase. X-ray-diffraction patterns for the treated alloys showed peaks corresponding to the L10 τ phase of the Mn-Al system.

At the next stage the synthesis of exchange-coupled nanocomposite magnets composed of magnetically hard (Mn-Al) and semi-hard (FeCo2B) phases will be performed.

[1] R. Skomski, G.C. Hadjipanayis, and D.J. Sellmyer, J. Appl. Phys. 105, 07A733 (2009).

[2] A. Iga, Japan J. Appl. Phys. 9, 415 (1970).

Fig. 2 Temperature dependence of spontaneous magnetization. Dark circles: PPMS data, low-T mode; open circles: PPMS data, high-T mode; open diamonds: LakeShore VSM data; continuous line: theoretical fit. Inset: x-ray diffraction pattern with incident beam along [001].

Figure 3 Temperature dependence of the leading anisotropy constant according to our data as well as those of Ref. 2.

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4-5. National Institute for Materials Science PPI: Dr. K.Hono, Co PI: Dr. H. Sepehri-Amin

Microstructure and magnetic properties of modeled low temperature phase MnBi thin film

Low temperature phase (LTP) MnBi with the hexagonal NiAs structure shows relatively high magnetocrystalline anisotropy of 0.9 MJ/m3 and moderate saturation magnetization of 0.73 at room temperature [1]. Of particular interest is that the magnetocrsytalline anisotropy of the LTP-MnBi phase enhances with increasing temperature, i.e. 2.2 MJ/m3 at 500 K [2]. Hence, Mn-Bi type permanent magnets with the main phase of LTP-MnBi have the potential to be used as moderate performance permanent magnets for elevated temperature applications without use of rare earth elements. Although there have been many studies on the development of Mn-Bi type permanent magnets since 1950th, there is no fundamental study on microstructure-coercivity relationships. Hence, in this project, modeled Mn-Bi type thin films have been fabricated at the University of Alabama, MINT center. We have studied the correlation between magnetic properties and microstructure of modeled Mn-Bi thin films at NIMS to provide guidelines for the future development of LTP-MnBi materials with good hard magnetic properties. The microstructure of the modeled Mn-Bi type thin films has been studied using a Titan G2 80-200 TEM with a probe corrector. Energy dispersive X-ray spectroscopy (EDS) was conducted in Titan G2 80-200 TEM using a Super-X EDX detector.

Figure 1 (a) shows the prepared thin film stack of 10 layers of Bi/Mn with thickness of 3.2 nm/2 nm for each layer, respectively, deposited on SiO2 substrate at room temperature. The as deposited film was annealed at 550˚C for 30 min. The in-plane and out-of-plane magnetization curve of the modeled thin film is shown in Fig. 1 (b). This film showed a saturation magnetization of 400 emu/cc and a high coercivity of 14 kOe. In order to understand the responsible mechanism for the high coercivity in the modeled thin film, the microstructure of the sample was studied using TEM. Fig. 1 (c) shows low magnification and high magnification bright field TEM images taken from the cross sectional view of the film. The diffraction contrast in the BF TEM images indicates two types of grains exist in the microstructure of the modeled thin film. High resolution (HR) TEM images and micro-beam diffraction patterns obtained from two different types of grains are shown in Fig. 1 (d) and (e). This result shows that the inverse cone shape phase correspond to the As-type Bi phase with the rhombohedral crystal structure. Micro-beam diffraction from the neighboring grain of Bi shows that this phase corresponds to the NiAs-type LTP-MnBi phase. High resolution TEM image from LTP-MnBi grain shows the lattice of c-plane of LTP-MnBi

Fig.1. a) Stack of layered Bi/Mn thin film. After deposition, the film was heat treated at 550˚C for 30 min. b) Magnetization curve of the modeled MnBi thin film shown in (a). c) Low and high magnification bright field (BF) TEM images from cross-sectional view of the Mn-Bi thin film. High resolution TEM image and micro-beam diffraction pattern from (d) Bi and (e) low temperature phase (LTP) MnBi grains, pointed out with arrows.

29

phase due to out of plane texture of this phase in the film. In order to have a better understanding on the distribution of different elements in the film, STEM-EDS analysis was employed. Figure 2(a) shows STEM HAADF image of the MnBi thin film and STEM-EDS maps of Ta, Ru, Bi, Mn, O, and Si. The Ta layer corresponds to the protection layer deposited on the film for the TEM sample preparation. The LTP-MnBi grains with diameter of around 20 nm can be seen to be isolated with Bi phase.

The stack design of the modeled Mn-Bi thin film with 10 layers of Bi(3.2 nm)/Mn(2 nm) before heat treatment suggests that the total composition of the film is in the Bi rich region of the phase diagram of Mn and Bi. Hence, Mn and Bi phase diagram suggests that after heat treatment at 550 °C and cooling, LTP-MnBi and Bi phase forms which was observed in the microstructure of the film shown in figures 1 and 2. Since LTP-MnBi grains with a size of around 20 nm are magnetically decoupled by Bi grains, magnetization reversal may occur by coherent rotation of the LTP-MnBi phase. This can be the reason for the high coercivity of 14 kOe in this film. However, the observed Bi grains have very large size leading to large reduction of the magnetization of the film. By decreasing the thickness of Bi grains via tuning the composition of the thin film to more closer to the stoichiometry of LTP-MnBi phase, we can enhance the magnetization of the MnBi film closer to the saturation magnetization of LTP-MnBi phase while maintaining high coercivity.

The number of Bi(3.2 nm)/Mn(2 nm) layers were also changed from 3 to 7 layers, as shown in Fig. 3 (a), and their magnetic properties was measured. Fig. 3 (b) shows the in-plane and out-of-plane magnetization curve of the modeled thin film with 5 layers of Bi(3.2 nm)/Mn(2 nm) and heat treated at 550 °C for 30min. This film also showed a high coercivity of 16 kOe at room temperature (Fig. 3 (b)). The microstructure of this film was studied using TEM. Bright field TEM image with out-of-plane easy axis is shown in Fig. 3 (c) and selected area diffraction pattern is shown in the inset. Combination of equiaxed and faceted grains can be seen in plane view of this film. STEM HAADF image and STEM-EDS maps of Mn and Bi are shown in Fig. 3 (d) to (f), respectively. Apart from MnBi grains, Mn rich phase can also be seen in the microstructure. Bi map shows that the Mn-rich grains are surrounded with Bi-rich phase. For better clarification of the existing phases, cross-sectional TEM image will be carried out. By optimizing the heat treatment condition, the formation of Mn-rich grains might be avoided. However, further studies are ongoing to clarify the existing phases in this sample to draw the mechanism of the obtained high coercivity in this film.

Figure 2: STEM HAADF image and STEM-EDS elemental maps of Ta, Ru, Bi, Mn, O, and Si of the film with a stack and magnetic properties shown in Fig. 1 (a) and (b).

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In summary, microstructure of high coercivity Mn-Bi type thin films, with 10 and 5 layers of Bi(3.2nm)/Mn(2nm), both heat treated at 550˚C for 30min, were studied using transmission electron microscopy. The fabricated film with 10 layers deposition of Bi(3.2nm)/Mn(2nm) and heat treated at 550˚C for 30 min showed 20 nm LTP-MnBi grains with a size of around 20 nm embedded in a Bi matrix. This microstructure suggested obtained high coercivity in this film is due to the magnetization reversal by coherent rotation mechanism. By reducing the thickness of Bi grains in the film, high coercivity with improved magnetization was achieved. In addition, Mn grains were observed in the out-of-plane view of the 5 layers deposited Bi(3.2nm)/Mn(2nm) film and heat treated at 550˚C for 30min. This might be due to not-optimum heat treatment condition on the film which led to remaining Mn grain without reaction with Bi layers. Further microstructure studies are necessary to clarify the phases for this film which is our ongoing research.

Reference:

[1] Tu Chen et al. IEEE Trans. MAG-10 (1974) 581.

[2] P. M. Oppeneer, V. N. Antonov, T. Kraft, H. Eschrig, A. N. Yaresko, and A. Ya. Perlov, J. Appl. Phys. 80, 1099 (1996).

Figure 3: a) Stack of 3, 5, and 7 layered Bi(3.2 nm)/Mn(2.0 nm) thin film. These films were heat treated at 550°C for 30 min. b) Magnetization curve of the modeled Mn-Bi thin film deposited with 5 layers of Bi(3.2nm)/Mn(2.0nm) and heat treated at 550°C. c) Bright field TEM image, d) STEM-HAADF image and STEM-EDS maps e) Mn and f) Bi from out-of-plane view of the film with 5 layers deposited Bi/Mn and annealed at 550˚C for 30min. g) STEM-EDS line scan of Mn and Bi from selected line shown in (f).

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4-6. TDK Corporation PPI: Dr. Shin-ichiro Itoh

(1) Review of the MnAl and MnBi magnets fabrication processes

The fabrication processes of MnAl and MnBi bulk magnets were reviewed. MnAl permanent magnets were mass-produced by Sanyo Special Steel Co., Ltd. The flow diagram of the production process of MnAl magnets is shown as Fig.1 [1-2]. At first, the starting alloy is made by a casting method such as gas atomization. The starting alloy is heat-treated around 1300K to form non-magnetic phase. Warm extrusion process is following to shape the bulk magnets. At this stage, phase trans ferromagnetic phase. The crystal orientation is induced at the same time and the anisotropic magnets are made without a magnetic field. The phase diagram of Mn-Al binary system is shown in Fig.2 [2]. The temperature of each process is indicated in the diagram. Because phase is metastable and the coexistence of and -Mn phases is more stable around 1000 K, the direct synthesis of MnAl single phase is likely to be impossible according to the thermodynamic prediction. The non-equilibrium phase transformation, however, has been utilized to form the metastable phase effecti production process was designed to fit the nature of the Mn-Al system.

Manganese bismuth bulk magnets were developed by the U.S. Naval Surface Weapons Center. Because the MnBi alloy shows a complex phase transformation around ferromagnetic phase ( -BiMn in Fig.4), which is called LTP (Low Temperature Phase) as well. It is not easy to obtain a pure MnBi ferromagnetic phase. Makino et al. proposed the improved fabrication process to obtain MnBi ferromagnetic phase with

Fig.2 Phase diagram of Mn-Al system Fig.1 Production flow diagram of MnAl magnets

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high yield [3]. The powder metallurgy process was employed and the bonded magnets were made. The process flow was summarized in Fig. 3. The mixture of Mn and Bi metallic powders was compacted and heat-treated at 250-260℃. The reaction was limited to temperature lower than the eutectic temperature (535K). Low temperature reaction enabled to high yield of the ferromagnetic phase.

The production processes of MnAl and MnBi magnets are quite different each other, because the optimal production process depends the materials nature.

(2) Preview of production process of Mn-based magnets

Figure 5 shows a general production process of the bulk magnets. The examples of methods for each stage are shown at the left side of the diagram. Three development subjects to produce high performance magnets are recognized as followed.

(i) Producing single-domain particles at powder fabrication stage

(ii) Treating powder without agglomeration to make the composite, if necessary

(iii) Attaining high density, while controlling grain growth

Fig.3 Production flow diagram of bonded MnBi magnets

Fig.4 Phase diagram of Mn-Bi system

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The (i) and (ii) subjects strongly depend on the materials. It is difficult to discuss at present. The Mn-based magnets to develop should have the controlled microstructure and nanostructure. It would be difficult to sinter with maintaining the controlled structures. The low temperature densification method would be necessary. A hot pressing or a spark plasma sintering (SPS) are the candidate methods. Recently, the SPS method was utilized for the SmFeN magnet which is unstable above 500℃ [5]. The bulk SmFeN magnets with high density and good performance was reported [5]. The problem may be long cycle time of pressing. Improving the productivity of hot pressing or SPS method may be required.

References:

[1] S. Kojima, Journal of the Magnetics Society of Japan, 6, 18 (1982) (in Japanese). [2] Y. Tanaka et al., Journal of the Japan Society of Powder and Powder Metallurgy, 47, 15 (2000) (in Japanese). [3] N. Makino and M. Suzuki, J. Jpn. Inst. Met. Mater., 24, 24 (1960) (in Japanese). [4] K. Oikawa et al., Mater. Trans. 52, 2032 (2011). [5] K. Takagi, AIST Today, 12, 22 (2012).

Fig.5 Production flow diagram of general bulk magnets

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5. Appendix

5-1. G8 Consortium Agreement

JOINT RESEARCH AND DEVELOPMENT CONSORTIUM AGREEMENT

(This Agreement has been fully executed with all the signatures of the partners’ organizations.)

INTRODUCTION

This JOINT RESEARCH AND DEVELOPMENT CONSORTIUM AGREEMENT, is executed and made effective as of May 31, 2013 (the "EFFECTIVE DATE") for the purpose of establishing a research consortium for the purpose of managing and operating all aspects, both scientific and administrative, of the G8 PROGRAM administered by The University of Alabama.

This AGREEMENT is made by and between the following institutions:

The Board of Trustees of The University of Alabama, for and on behalf of its constituent institution, The University of Alabama (“UA”); and

The University of Delaware (“UD”); and

The National Institute for Materials Science, Japan (“NIMS”); and

Technische Universität Darmstadt, Karolinenplatz 5, 64289 Darmstadt, Germany ("TU”) for the department of Material Sciences, Functional Materials Prof. Dr. Oliver Gutfleisch; and

Max-Planck Institute for Intelligent Systems, Germany ("MPI"); and

TDK, Japan ("TDK");

The above parties to this AGREEMENT, are singularly and collectively referred to herein as "MEMBERS."

WITNESSETH, THAT:

WHEREAS the MEMBERS filed an application to be funded by the International Program G8. They succeeded and UA is the coordinator. The G8 program is based on the principle that each MEMBER is individually funded by a national institution and therefore bound by national legislation and the national regulations of the respective institution.

WHEREAS, The UA Center for Materials for Information Technology (“MINT”), was awarded and NSF Grant, Award Number CMMI-1229049 entitled “G8 Initiative: High Performance Permanent Magnets sustainable for Next Generation (HPPMSNG)” (the “GRANT”) to establish the G8 Research Consortium (“G8 RC”), consisting of six member organizations (“MEMBERS”); and by this AGREEMENT the MEMBERS

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have reached agreement relating to the management and operation of the G8 RC, and the research to be carried out thereunder, and have reached agreement relating to the ownership, prosecution and licensing of intellectual property resulting from work accomplished within the G8 RC, and the resolution of related operational and legal issues which may arise in the operation of the G8 RC; and

WHEREAS, UA MINT, as the awardee institution of the GRANT, has agreed to receive and administer the GRANT in accordance with this AGREEMENT, and has agreed to provide an individual to serve as the GRANT’s Lead Principal Investigator (the " LPI"), who will serve as LPI in accordance with the duties and responsibilities described herein in Article 5, and UA will also provide a management and operations group to administer the GRANT as described herein; and

WHEREAS, the MEMBERS by this AGREEMENT have agreed that this consortium is established for the following purposes:

1. To support research on topics of global relevance through a multinational approach, recognizing that global challenges need global solutions.

2. To support collaborations between experts in research areas related to the global challenge of materials efficiency to address replacement of scarce and expensive elements, notably those critical for energy applications.

3. To support interdisciplinary projects with the potential of creating a step change in the approach taken towards the sustainable use of material resources and the contribution and impact.

4. To emphasize the potential future role of manufacturing in supporting a sustainable global economy, and encompasses all parts of the materials hierarchy.

NOW, THEREFORE, in consideration of the terms and conditions and mutual covenants set forth herein, and the obligations and responsibilities resulting therefrom and hereby undertaken, the MEMBERS to this AGREEMENT, do hereby agree as follows.

ARTICLE 1 - ORGANIZATION

1.1. Grant Administration. The MEMBERS each agree to cooperate and use their best efforts to carry out their respective roles in the research program of the G8 RC in accordance with the terms and conditions of this AGREEMENT as it applies to each member, in accordance with the respective national legislation and in accordance with the respective national guidelines, applicable to each member. This agreement incorporates all attachments hereto including the Grant Agreement for NSF Grant Award Number CMMI-1229049 effective September 1, 2012 and expiring August 31, 2016, with its terms and conditions, a copy of which is incorporated by reference and attached to this AGREEMENT as Attachment 1.

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1.2. The Science. The scientific endeavor of the G8 RC shall be carried out by INVESTIGATORS (see Article 3) under the leadership of MINT along with two committees, the International Oversight Committee (“IOC”) and the Consortium Advisory Committee (“CAC”) (see Article 2). The institutions which employ the INVESTIGATORS must be MEMBERS and participate as such in the G8 RC (see Article 4.).

1.3. The Administration. The administration of the G8 RC shall be carried out by the UA MINT Center. (see Article 5).

1.4. Legal Status of the G8 RC. The G8 RC is a research consortium and is not a legal entity with the capacity to enter into contracts or otherwise conduct business. All legal transactions contemplated by this AGREEMENT shall be carried out through the MEMBERS.

ARTICLE 2 - LEADERSHIP

2.1. General. The leadership of the G8 RC shall be provided by UA MINT, along with review and consultation by the IOC and the CAC in accordance with the terms of this AGREEMENT and in accordance with the respective national guidelines: research grant programme .

2.2. The International Oversight Committee ("IOC"). The IOC includes the Lead Principal Investigator (“LPI”) and the Partner Principal Investigators (“PPIs”), membership may also be held by representatives of the G8 RC partner organizations. The IOC reviews the progress and recommends necessary adjustments to consortium activities. IOC meetings will be held bi-monthly via video conference and/or at other occasions including major international conferences.

2.3. The Consortium Advisory Committee ("CAC"). The CAC shall be established to oversee the activity from the market demand and technology transfer issues resulting from the scientific research. The CAC will act as an advisor to the IOC on market and technology issues. The CAC will meet at the time of the UA MINT Review Meeting.

2.3.1. The CAC will be expected to comply with the confidentiality provisions set forth in Article 7 herein, and members of the CAC who are not PPIs will be required to comply with the confidentiality provisions as well.

2.4. MINT Consortium Committee (“MCC”). In addition to the IOC and the CAC, UA will have its own MINT Consortium Committee which will include the LPI and four MINT faculty team members representing theory, experiment and characterization areas. The responsibility of the MCC is to keep the MINT team in close communication within the MINT as well as the entire consortium.

ARTICLE 3 - G8 RC INVESTIGATORS

3.1. G8 RC INVESTIGATORS. The investigators of the G8 RC shall include following:

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3.1.1. Takao Suzuki, Lead Principal Investigator, MINT Center, University of Alabama, USA

3.1.2 Kazuhiro Hono, Partner Principle Investigator, National Institute For Materials Science, Japan

3.1.3 Oliver Gutfleisch, Partner Principle Investigator, Technische Universität Darmstadt, Germany

3.1.4 George Hadjiapanayis, Partner Principle Investigator, University of Delaware, USA

3.1.5 Shinichiro Ito, Partner Principle Investigator, TDK, Japan

3.1.6 Helmut Kronmuller, Partner Principle Investigator, Max-Planck Institute for Intelligent Systems,

Germany

3.2. INVESTIGATORS as Employees. The G8 RC has no employees, and for purposes of this AGREEMENT, each INVESTIGATOR shall serve only as an employee of the MEMBER by which she or he is employed or an equivalent as provided herein.

ARTICLE 4 - INSTITUTIONS

4.1. Status of Institutions. The relationships of the parties to each other will be that of independent contractors and not as agents, joint venturers or partners.

4.2. Participation of Individuals in G8 RC Research. MEMBERS shall each limit the participation in G8 RC research to those individuals who are legally obligated to assign their respective right in any and all INVENTIONS (as such terms are defined in Article 9), and any patent rights arising therefrom, to the subject MEMBER.

4.3. Modification of AGREEMENT by ORIGINAL PARTIES. Except as expressly set forth in this AGREEMENT, it is understood and agreed that this AGREEMENT may only be modified by the ORIGINAL PARTIES in accordance with Article 15.1 below.

ARTICLE 5 - MANAGEMENT

5.1. General. The UA MINT Center will be responsible for administration of the consortium activities.

5.1.1. The administrative responsibilities of the consortium will be under the direction of the LPI, Dr. Takao Suzuki, the Director of the MINT Center. The MINT Center office will keep all PPIs informed of the progress of activities through various means including the consortium website, an annual Consortium Newsletter, and progress reports.

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5.2. Intellectual Property Coordination

Each MEMBER shall be responsible for the management of its intellectual property, including without limitation the protection of such intellectual property and the licensing of the same in accordance with the intellectual property provisions of this AGREEMENT and the respective national requirements/regulations which shall prevail.

ARTICLE 6 - CONSIDERATION

6.1. The mutual obligations undertaken herein, and the rights granted under this AGREEMENT, represent the consideration for this AGREEMENT.

ARTICLE 7 - CONFIDENTIAL INFORMATION

7.1. "CONFIDENTIAL INFORMATION" shall mean all information provided by one party to another party and clearly identified as confidential by the transmitting party at the time of disclosure. "CONFIDENTIAL INFORMATION" shall also include (i) all information identified as “CONFIDENTIAL INFORAMTION” provided at any IOC, CAC or MINT meeting, G8 RC-related meeting by any MEMBER, including without limitation telephone and video conference calls, and, (ii) all information relating to intellectual property, regardless of whether or not such information is identified or marked, or a record provided, of such information as confidential. Specifically excepted from the definitions of CONFIDENTIAL INFORMATION set forth above is all information:

7.1.1. already known by the receiving party at the time of disclosure as can be demonstrated by competent proof;

7.1.2. publicly known without the wrongful act or breach of this AGREEMENT by the receiving party;

7.1.3. rightfully received by the receiving party from a third party having the lawful right to make such a disclosure, where said disclosure is made without an express obligation of confidence;

7.1.4. approved for release by written authorization of the disclosing party;

7.1.5. independently developed by the employees or agents of the receiving party without the use of the CONFIDENTIAL INFORMATION provided by the other party as can be demonstrated by competent proof;

7.1.6. disclosed pursuant to any judicial or government request, requirement or order (including the disclosure requirements of CFR 1.56), provided that the party so disclosing takes reasonable steps to provide the other party sufficient prior notice in order to contest such request, requirement or order and provided that such CONFIDENTIAL INFORMATION otherwise remains subject to the obligations of confidentiality and restricted use set forth in this Article; or

7.2. The party receiving the CONFIDENTIAL INFORMATION agrees to hold that information in trust and confidence for the transmitting party, using the same care and discretion that the receiving party uses

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with similar information which it considers confidential. The receiving party will not use CONFIDENTIAL INFORMATION other than for the benefit of the G8 RC research relating to this AGREEMENT and, except as may be provided for in Article 8 regarding publication herein, neither party will disclose such information without authorization from the other party. The confidentiality and restricted use provisions set forth in this Article 7 shall remain in effect for each subject disclosure for a period of three (3) years from the date of the subject disclosure.

7.3. For avoidance of doubt and notwithstanding anything to the contrary in this AGREEMENT, it is understood and agreed that, upon the direction of the LPI, UA may, acting for and on behalf of the G8 RC, enter into one or more confidential disclosure agreements with prospective G8 RC participants for the purpose of discussing G8 RC-related activities Such disclosure of CONFIDENTIAL INFORMATION is strictly limited to the extent necessary for the purposes of the subject discussion and no disclosure of CONFIDENTIAL INFORMATION covering intellectual property shall be made without the express prior written approval of the owner of such CONFIDENTIAL INFORMATION (such approval not to be unreasonably withheld or delayed).

ARTICLE 8 - DATA SHARING, PUBLICATION AND OTHER USE

8.1. It is understood and acknowledged that prompt sharing of data resulting from RESEARCH with MEMBERS, and the scientific community is a key goal of the G8 RC. Accordingly, each MEMBER shall expedite sharing of the results of their respective RESEARCH (“RESEARCH RESULTS”) in accordance with this AGREEMENT and the respective national requirements/regulations which shall prevail. UA MINT shall serve as the consortium office and will archive all reports and place them on a password-protected website for MEMBER´s access. A yearly progress report will be published that summarizes the research outcomes collected.

8.2 Within the G8 RC each MEMBER shall expedite sharing of data as follows:

8.2.1. Each MEMBER shall promptly send its respective RESEARCH RESULTS to the LPI or his / her designee. The LPI or his / her designee shall be responsible for archiving and disseminating RESEARCH RESULTS to the MEMBERS.

8.3. It is understood and agreed that the prompt publication and public dissemination of RESEARCH RESULTS are of the utmost importance, and to that end, all MEMBERS shall publish (or otherwise disclose publicly to the world-wide research community) RESEARCH RESULTS in accordance with the publication policy of that MEMBER and the national regulations of the respective funding institution. It is further understood and agreed that the publishing / disclosing party shall provide a copy of each proposed publication / public disclosure to the LPI and to the other scientists who are contributing parties to the proposed publication / public disclosure prior to submission and with sufficient time (in any event no fewer than fifteen (15) days for peer-reviewed publications) to allow the other contributing parties to offer comments and suggestions, such comments and suggestions to be considered in good faith.

8.3.1. It is understood and agreed that if one or more potentially patentable INVENTION is identified

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by one or more of the appertaining contributing MEMBERS, submission / public disclosure may be delayed by providing written request for a delay to the lead author prior to proposed publication submission date, such delay to be for the sole purpose of allowing the filing of patent application(s) and to be no longer in duration than sixty (60) days from the date of notice. For avoidance of doubt, if no written request for delay is received the lead author within the specified time then it shall be conclusively presumed that the proposed publication may proceed without delay.

8.4. Subject to restrictions imposed in Article 7 and the relevant terms and conditions of Article 9, each MEMBER shall be free to use any RESEARCH RESULTS to the extent such RESEARCH RESULTS are necessary for the performance of its G8 RC-related research responsibilities.

ARTICLE 9- INTELLECTUAL PROPERTY AND SHARING OF NOVEL RESEARCH RESOURCES

9.1. Existing Intellectual Property. It is recognized and understood that certain existing and future inventions and technologies are the separate property of certain MEMBERS (“EXISTING IP”) and, except as expressly stated in this AGREEMENT, it is agreed that such EXISTING IP is not affected by this AGREEMENT, and further agreed that no MEMBER shall have any claims to or rights in another MEMBER’s EXISTING IP. Notwithstanding the foregoing, however:

9.1.1. To the extent (but only to that extent) that the owner / licensee / sublicensee of such EXISTING IP makes it available for RESEARCH by designating it in accordance with the procedure outlined in Article 9.1.2 below, the MEMBER so designating the EXISTING IP covenants not to sue the MEMBER using the EXISTING IP for the use of such EXISTING IP, but such covenant not to sue shall only be to the extent the use of the subject EXISITING IP is necessary, and for the duration of time required, to complete the subject RESEARCH. If an owner / licensee / sublicensee of such EXISTING IP does not have the legal right to make such intellectual property available as described above, then such owner / licensee / sublicensee shall use its reasonable best efforts to obtain the legal right so required.

9.1.2 It is understood and acknowledged that certain technologies that fall within the scope of EXISTING IP may be utilized or further developed in the performance of RESEARCH and potentially could be utilized in one or more commercial products that might arise from the G8 RC research. MEMBERS shall promptly designate the availability of EXISTING IP to the LPI and shall, as they become aware of changes in the status of EXISTING IP (for example, commencement of optioning / licensing discussions), file updates with the LPI.

9.2. Inventions Defined and Disclosure. For the term of this AGREEMENT, all inventions, developments, and / or discoveries directly resulting from RESEARCH including without limitation research tools, ("INVENTIONS," which defined term shall include the singular and plural and shall collectively include joint inventions as described in 9.4 below, when applicable) shall be promptly disclosed in writing on the applicable institutional invention disclosure form to the employer of the scientists(s) involved in RESEARCH from which the subject INVENTION arose. Within sixty (60) days of receipt of such an INVENTION disclosure, the disclosing MEMBER shall disclose the subject INVENTION to the G8 RC by

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sending a copy of the applicable institutional invention disclosure form to the LPI (or his / her designee). Each such INVENTION disclosure shall be subject to the confidentiality provisions set forth in Article 7.

9.2.1. The LPI or his / her designee shall disseminate, under the confidentiality provisions of Article 7 of this AGREEMENT, the subject INVENTION disclosure to the MEMBERS as may be required by the mission of the G8 RC and the terms of this AGREEMENT.

9.2.2. If substantive action is proposed to be taken with regard to a particular INVENTION (for example, if negotiations for options / licenses begin), such proposed action should be promptly reported to the LPI.

9.3. Inventorship and Ownership of INVENTIONS. Title to each INVENTION (and any patent rights arising therefrom) shall reflect inventorship and it is understood and agreed that MEMBERS have policies in place that ensure that ownership shall be in the employers of the inventor(s) of the INVENTION. MEMBERS which are owners of a subject INVENTION by virtue of that INVENTION having been invented by one or more of their respective employees are hereby defined and referred to herein as "OWNER(S)").

9.4. Joint Inventions. If there is more than one OWNER of an INVENTION, then the respective obligations under this Article 9 and other pertinent issues (which may include filing, prosecuting, and maintaining appropriate patent protection for the INVENTION, marketing of the INVENTION, sharing of any revenues derived from option and / or license agreements for the subject INVENTION (and any patent rights arising therefrom and the like) shall be determined by mutual written agreement among the OWNERS of the subject INVENTION, which agreement shall be negotiated in good faith between the OWNERS.

9.5. Patenting of INVENTIONS. Each OWNER(S) shall have the sole and / or joint responsibility evaluating his/ their INVENTIONS, and, if appropriate, the filing, prosecuting, and maintaining of the patent protection for its INVENTIONS. All of the expenses of such protection shall be the responsibility of the OWNER(S).

9.5.1. In determining how to manage a subject INVENTION , the OWNER(S) shall consider pertinent intellectual property and licensing matters (including, but not limited to the need, to pursue patent protection and the appropriate scope thereof, the appropriate nature of option and / or license arrangements, appropriate mechanisms for sharing of the subject INVENTION with the broader research community) in a manner consistent with (i) the goals of the G8 RC and (ii) the provisions of this AGREEMENT.

9.5.2. Subject to the exceptions set forth in Article 7, but notwithstanding anything else to the contrary in this AGREEMENT, all information relating to filing, prosecution, maintenance, defense, infringement and the like, regarding subject patent rights (no matter how disclosed) shall be considered the CONFIDENTIAL INFORMATION of the appertaining OWNER(s) and subject to the obligations of restricted use and non-disclosure set forth in Article 7. It is understood and agreed that, notwithstanding anything to the contrary in this AGREEMENT, for the purposes of maintaining the

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obligations of restricted use and non-disclosure as regards patent rights CONFIDENTIAL INFORMATION, the provisions of Article 7 and this Article 9 shall survive and remain in effect as regards patent rights CONFIDENTIAL INFORMATION following any termination of this AGREEMENT.

9.5.4. Nothing in this AGREEMENT shall be deemed to be a representation or warranty by any of the OWNER(S) of the validity of any INVENTION and / or patent rights or of the accuracy, safety, efficacy, or usefulness, for any purpose, of any INVENTION and / or patents. No OWNER of a subject INVENTION and /or patent rights shall have any liability whatsoever to any third parties for or on account of any injury, loss, or damage, of any kind or nature, sustained by, or any damage assessed or asserted against, or any other liability incurred by or imposed upon any person or entity, arising out of or in connection with or resulting from the production or use of INVENTION and / or patent rights.

9.6. Licensing of INVENTIONS. Each OWNER shall have the sole and/or joint responsibility for licensing or distributing their INVENTIONS. OWNER(S) shall proceed with licensing or distribution in a manner consistent with (i) the scientific goals of G8 RC and (ii) the provisions of this AGREEMENT, the national regulations of the respective institution and national legislation, subject to the retention of rights granted herein. In addition to any rights in INVENTIONS associated with ownership to which MEMBERS may be entitled under this Article 9 any option or license granted for an INVENTION shall be limited by and subject to the restrictions and licenses granted under this AGREEMENT as follows:

9.6.1. Non-exclusive License of INVENTIONS to all MEMBERS Each MEMBER is hereby granted a non-exclusive, non-commercial, sublicenseable license to use each INVENTION (and any patent rights arising therefrom) only for the performance of its own non-commercial education and research. Without license fee, royalties, other financial consideration, or any other consideration other than the consideration herein;

9.6.2. If an exclusive option or exclusive license is contemplated for a particular INVENTION such action should be promptly reported to the LPI (or his / her designee). As necessary the LPI in consultation with the IOC and CAC, will evaluate and make recommendations regarding the action.

9.6.3. Notwithstanding the foregoing or anything else to the contrary in this AGREEMENT, it is understood and agreed that insofar as rights to INVENTIONS are granted herein pursuant to Article 9.6.1 this grant does not include any rights that may be held by another party, that may be required to practice the INVENTIONS. It is agreed that the grant of rights pursuant to Article 9.6.1 does not extend EXISTING IP or any other dominating intellectual property which may be required for the practice of an INVENTION.

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9.6.4. Each nonexclusive licensee agrees to indemnify, hold harmless and defend - in case of gross negligence or intent - (to the maximum extent that the subject licensee is allowed by applicable law including without limitation state tort-claim statutes) each OWNER of the subject INVENTION and of any patent rights arising therefrom and the members of their respective governing boards, officers, employees, medical and professional staff, faculty and agents, and their respective successors, heirs and assigns (the "INDEMNITEES"), against any and all damages, claims, suits, losses, damages, costs, fees, and expenses (including without limitation reasonable attorney fees and expenses of litigation) and incurred by or imposed upon the INDEMNITEES or any one of them in connection with any claims, suits, actions, demands or judgments arising out of the non-exclusive licensee's exercise of the subject non-exclusive license. No non-exclusive licensee shall be responsible for the gross negligence or intentional wrong doing of any of the OWNER(S). This Article 9.6.4. shall survive the termination of this AGREEMENT.

9.6.5. Each non-exclusive licensee shall maintain in force at its sole cost and expense, with reputable insurance companies (or through self-insurance), liability insurance, or self-insurance, in an amount sufficient to protect against liability under Article 9.6.4 above. This Article 9.6.5. shall survive the termination of this AGREEMENT.

9.6.6. Nothing in this AGREEMENT shall be deemed to be a representation or warranty by any of the OWNERS of the validity of any INVENTION (or of any patent rights arising therefrom) or of the accuracy, safety, efficacy, or usefulness, for any purpose, of any INVENTION (or any patent rights arising therefrom) non-exclusively licensed pursuant to Article 9 of this AGREEMENT.

9.7. Governmental Rights. It is understood and acknowledged that, notwithstanding anything to the contrary in this AGREEMENT, that all INVENTIONS (and any patent rights arising therefrom) which arise during the performance of research funded in part or wholly by the United States government will be subject to, and all licenses of such INVENTIONS (and any patent rights arising therefrom) shall include appropriate provisions relating to, the rights retained by the United States government as set forth in 35 U.S.C. §§ 201-211, and the regulations promulgated thereunder, as amended, or any successor statutes or regulations. In addition, it is understood and acknowledged that other sovereign governments may have certain rights to INVENTIONS (and any patent rights arising therefrom) that arise during the performance of research funded in part or wholly by that sovereign government.

ARTICLE 10 - COMPLIANCE WITH LAWS

10.1. The ORIGINAL PARTIES to this AGREEMENT and all those bound by this AGREEMENT agree to comply with laws and regulations of their respective home country which may be applicable to the research and other projects which may be undertaken by the G8 RC.

ARTICLE 11 - TERM OF AGREEMENT AND TERMINATION

11.1. This AGREEMENT shall be effective as of the EFFECTIVE DATE and shall remain in effect until August 31, 2016. This AGREEMENT may be extended at the end of the term of the AGREEMENT upon the written agreement of the PARTIES.

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11.2. Termination as a party to this AGREEMENT and / or participant in the G8 RC:

11.2.1. A party shall be terminated as a party to this AGREEMENT immediately upon its withdrawal from participation in the G8 RC, which withdrawal shall be indicated by notice to the LPI in writing, or upon that party's termination from participation in the G8 RC.

ARTICLE 12 - USE OF A PARTY'S NAME OR G8 RC MARKS

12.1. No party will, without the prior written consent of the affected party(ies), (a) use in advertising, publicity or otherwise, the name or image of any employee, faculty member, or agent, any trade-name, trademark, trade device, service mark, symbol, or any abbreviation, contraction or simulation thereof owned by that party, or (b) represent, either directly or indirectly, that any product or service of that party is a product or service of the representing party or that it is made in accordance with or utilizes the information or documents of that other party; provided, however, it is agreed that MEMBERS and their employees as applicable, may be listed as G8 RC participants on the G8 RC website and in G8 RC publications, and MEMBERS may include references to the G8 RC and this AGREEMENT as may be required by statute.

12.2. Except as set forth in Article 8.5 above relating to publications, no party will, without the prior written consent of MINT, (a) use in advertising, publicity or otherwise, the name or image of any employee or agent, any trade-name, trademark, trade device, service mark, symbol, or any abbreviation, contraction or simulation thereof owned by G8 RC, or (b) represent, either directly or indirectly, that any product or service of that party is a product or service of the representing party or that it is made in accordance with or utilizes the information or documents of the G8 RC.

ARTICLE 13 - NOTICE

13.1. Any notice or other communication required or permitted under this AGREEMENT will be in writing, shall be delivered not only to the party entitled to receive the notice but also by copy to the LPI who will copy all MEMBERS with that notice, and such notice will be deemed given as of the date it is (a) delivered by hand, or (b) mailed, postage prepaid, first class, certified mail, return receipt requested, to the party at the address listed below or subsequently specified in writing, (c) sent via electronic mail, or (d) sent, shipping prepaid, return receipt requested, by national courier service, or the party at the address listed on the MEMBERS roster which is attached hereto at Attachment 2 and incorporated herein by reference.

13.2. Any notice or other communication required or permitted under this AGREEMENT to be delivered to the G8 RC shall be delivered in accordance with 13.1. above to MINT, at the following address:

Center for Materials for Information Technology (MINT)

University of Alabama

Box 870209

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Bevill Building 2005

Tuscaloosa, Alabama 35487

ATTENTION: G8 Research Consortium, Dr. Takao Suzuki

Phone: 205-348-2508

Fax: 205-348-2346

Email: takaosuzuki@mint.ua.edu

ARTICLE 14 - ASSIGNMENT

14.1. This AGREEMENT governs a research collaboration. None of the parties may assign, delegate or otherwise transfer any of its rights or obligations under this AGREEMENT without the prior written consent of the LPI.

ARTICLE 15 - ENTIRE AGREEMENT

15.1. This AGREEMENT incorporates all attached Schedules by reference and includes those attached Schedules as part of this AGREEMENT, and they contain the entire agreement and understanding between the MEMBERS as to its subject matter. It merges all prior discussions between the MEMBERS, and none of the MEMBERS will be bound by conditions, definitions, warranties, understandings, or representations concerning such subject matter except as provided in this AGREEMENT or as specified on or subsequent to the EFFECTIVE DATE of this AGREEMENT in a writing executed by the MEMBERS and signed by properly authorized representatives of all of the MEMBERS.

Except as expressly authorized elsewhere herein, this AGREEMENT and all Attachments may only be modified by written agreement executed by the MEMBERS and duly signed by persons authorized to sign agreements on behalf of all of the PARTIES.

15.2. If there is a conflict in the terms or interpretation thereof between this AGREEMENT and any Attachment or hereto, or any other agreement executed as part of the G8 RC, and unless explicitly provided otherwise, the terms and conditions of this AGREEMENT shall control.

In the event of conflict between the conditions of this AGREEMENT and the respective national legislation/ guidelines, the latter shall prevail.

15.3. Decisions relating to the management and operations of the G8 RC not specifically addressed in this AGREEMENT and related documents may be made by and in the discretion of the LPI who may consult with the IOC, CAC and MINT as required.

ARTICLE 16 - WAIVER

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16.1. The failure of a party in any instance to insist upon the strict performance of the terms of this AGREEMENT will not be construed to be a waiver or relinquishment of any of the terms of this AGREEMENT, either at the time of the party's failure to insist upon strict performance or at any time in the future, and such terms will continue in full force and effect.

ARTICLE 17 - SEVERANCE

17.1. Each clause of this AGREEMENT is a distinct and severable clause and if any clause is deemed illegal, void or unenforceable, the validity, legality or enforceability of any other clause or portion of this AGREEMENT will not be affected thereby.

ARTICLE 18 - DISPUTE RESOLUTION

18.1. The MEMBERS to this AGREEMENT agree to attempt to resolve promptly any dispute arising out of or relating to this AGREEMENT by good faith negotiation. Provided, however, if such attempts at dispute resolution shall fail, and before litigation is commenced, the MEMBERS to this AGREEMENT agree to submit any such dispute for resolution, upon written request by either party, by mediation in accordance with acceptable standards of business transactions mediation.

18.1.1. The mediation shall take place at a time and place selected by mutual agreement of the MEMBERS.

18.1.2. One mediator selected by mutual agreement of the MEMBERS shall mediate the dispute.

18.1.3. The MEMBERS shall make a good faith effort to reach a settlement of the dispute at issue.

ARTICLE 19 - MISCELLANEOUS

19.1. All captions, titles and article headings contained in this AGREEMENT are inserted only as a matter of convenience and reference, and references to specific articles shall refer to that article and all subheadings thereof unless expressly stated otherwise. They do not define, limit, extend or describe the scope of this AGREEMENT or the intent of any of its provisions.

19.2. Each MEMBER will do such further acts, including execution and delivering additional agreements or instruments as the other may reasonably require, to consummate, evidence or confirm the agreements contained in this AGREEMENT.

19.3. All pronouns will be deemed to refer to the masculine, feminine or neuter, and singular or plural, as appropriate.

19.4. This AGREEMENT may be executed in any number of counterparts, each of which shall be an original, but such counterparts shall together constitute but one and the same AGREEMENT.

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19.5. Except as otherwise expressly provided in this AGREEMENT, all covenants, representations and warranties, express or implied, shall survive the execution of this AGREEMENT, and shall bind the MEMBERS until the MEMBERS have fulfilled all of their obligations.

19.6 COUNTERPARTS This AGREEMENT may be executed in counterparts, by facsimile or PDF scanned document, each of which shall be deemed to be an original, but all of which taken together, shall constitute one and the same AGREEMENT.

AS WITNESS the MEMBERS have caused this AGREEMENT to be duly signed by their undersigned authorized representatives, the day and year first above written.

END OF AGREEMENT. SIGNATURE PAGES AND ATTACHMENTS FOLLOW.

All signatures have been entered as of July 11, 2013.

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5-2. The Program of the 1st Workshop

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5-3. The List of the Meetings held for the International Organizing Committee

1. 1st Meeting: September 3 (M), 2012, Nagasaki, Japan (During the Rare Earth Permanent Magnet Conference)

2. 2nd Meeting: January 17 (Th),2013, Chicago, U.S.A. (During the joint MMM/Intermag Conference)

3. 3rd Meeting: April 8 (M),2013, Tuscaloosa, AL (During G8 Workshop)

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6. Acknowledgements All the PI, PPI and Co-PI at the organizations involved in this project would like to express their gratitude for the supports by the G8 national councils of USA (NSF), Japan (JSPS) and Germany (DFG). The international and interdisciplinary efforts are essential for the success of the present project, and for this reason, we are all grateful for the supports and encouragement given by their respective organizations. Finally, but not least, PI Takao Suzuki would like to thank all the PPIs and Co-PIs for their constant supports and invaluable advise for this project, without which we were unable to publish this annual report with high quality contents. Looking forward to working closely for the second year of this project!

Principle Investigator, Dr. Takao Suzuki University of Alabama, Tuscaloosa, AL, U.S.A.

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