1 m.rotter „magnetostriction“ course lorena 2007 new topics fe-ga magnetic shape memory effect...
Post on 21-Dec-2015
216 views
TRANSCRIPT
1M.Rotter „Magnetostriction“ Course Lorena 2007
New Topics
• Fe-Ga• Magnetic Shape Memory Effect• Gd Compounds, Gd-Si• RE Metals Sm, Tm• MEP
2M.Rotter „Magnetostriction“ Course Lorena 2007
FeGa ?
Lattice parameter plots of solute element content in Fe: ( ) Fe–Al alloys, ( ) Fe–Be alloys, and (×) Fe–Ga alloys
Magnetostriction curves of (a) Fe–15 at. % Ga, directionally cast (DS) and heat treated at 600 °C for 1 h and (b) Fe–15 at. % Ga–5 at. % Al, directionally cast (DS) and heat treated at 1100 °C for 1 h and 730 °C for 1 h
N. Srisukhumbowornchai and S. Guruswamy Journal of Applied Physics 90( 2001) 5680
3M.Rotter „Magnetostriction“ Course Lorena 2007
4M.Rotter „Magnetostriction“ Course Lorena 2007
0 1 2 3 4 50
30
60
90
120
Fe0.725
Ga0.275
l /
l (p
pm
)
0H (T)
AS CAST 150 K 280 K
HT: 1100oC/1h + 875 oC/1h 150 K 280 K
R. Grössinger, R. Sato, H. Müller, S. Heiss, 2006
5M.Rotter „Magnetostriction“ Course Lorena 2007
Magnetic Shape Memory Effect
Principle of magnetic field induced re-orientation of martensitic variants.
Ferromagnetic shape memory alloys (FSMA) are smart materials possessing not only ferromagnetic as well as thermal shape memory properties but also large magnetic field induced strains. In single crystalline Ni2MnGa bulk material, strains as large as 10% have been realized.
6M.Rotter „Magnetostriction“ Course Lorena 2007
Gd5(SixGe1-x)4
Morellon et. al. 2000
Morellon et. al. 2000
O(II)O(I)
TN= 127 KTC= 81 K
7M.Rotter „Magnetostriction“ Course Lorena 2007
Samarium
0 5 10 15 20 25 30 35 40
0,00
0,05
0,10
0,15 <1120> 4.2 K <0001> 4.2 K <0001> 20.4 K
Sm
M ( B
/ato
m)
0H (T)
K. McEwen et al. J. Phys. F: Metal Phys.4 (1974) 2264
Magnetization
8M.Rotter „Magnetostriction“ Course Lorena 2007
0 50 100 150 200 250 300-2,0x10-3
0,0
2,0x10-3
4,0x10-3
6,0x10-3
8,0x10-3
1,0x10-2
TN
T1
c
bV/V = (a+b+c)/3
a
SmH = 0
i = (l/
l)i
T (K)
Samarium
Thermal Expansion
9M.Rotter „Magnetostriction“ Course Lorena 2007
Samarium
Magnetostriction
10M.Rotter „Magnetostriction“ Course Lorena 2007
Tm
.... Strongly anisotropic Systems have to be measured with great care !!!
From Zochowski et al.[cap dilatometry J. Magn. Magn. Mat. 104-107, 1515 (1992). ].
?
TN=54K
11M.Rotter „Magnetostriction“ Course Lorena 2007
Forced magnetostriction of Tm a single crystal. Circles represent the data measured by Zochowski et al.[cap dilatometry J. Magn. Magn. Mat. 104-107, 1515 (1992). ]. Squares represent the data obtained by Barcza. [TU Vienna]. Crosses represent the neutron diffraction data obtained at IN12. Triangles the data obtained by A. Lindbaum glueing the sample [TU Vienna].
Tm