antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor...
TRANSCRIPT
- Slide 1
- Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor Kitaoka lab Itohara Keita
- Slide 2
- Contents Introduction Meissner effect Type and Type superconductor La 2-x Sr x CuO 4 Experimental method Magnetic neutron diffraction Experimental data and discussions Summary
- Slide 3
- Meissner effect Magnetic field H B=M+H=0
- Slide 4
- Type and type superconductor Magnetic field H Type Type Normal state Perfect diamagnetism Perfect diamagnetism Vortex state
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- La 2-x Sr x CuO 4 Use single crystals of underdoped La 2-x Sr x CuO 4 00.10.20.3 0 50 100 150 200 250 300 350 Temperature[K] Sr doping (x) superconductivity Antiferromagnetism Spin glass
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- Neutron diffraction Braggs law 2dsin= n Neutron diffraction is closely related to X-ray powder diffraction Merit Neutrons have stronger penetration than X-ray and interact directly with the nucleus of the atom Samples sizes are relatively large compared to those used in X-ray diffraction
- Slide 7
- Magnetic neutron diffraction Neutrons are uncharged, they carry a spin interact with magnetic moments reveal the microscopic magnetic structure of a material
- Slide 8
- Experimental data (1) Superconductivity characterized by zero-resistivity at the much lower temperature T(K) T c =29K
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- Experimental data (2) superconductivity and antiferro coexist throughout the bulk of the material antiferromagnetism The applied field that imposes the vortex lattice also induces antiferromagnetic order
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- Experimental data (3) The order increases rapidly with small fields, reflecting the linear dependence of vortex density on field Vortex core
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- Magnetic correlation length >400 Superconducting coherent length 20 avav H=1T 500 130 H=14.5T
- Slide 12
- Summary In the high-temperature superconductivity, La 2-x Sr x CuO 4 (x=0.10),there is the field-induced antiferromagnetism The field-induced antiferromagnetism is intrinsic And superconductivity and antiferromagnetism coexist throughout the bulk of the material 00.10.20.3 0 50 100 150 200 250 300 350 Temperature[K] Sr doping (x) superconductivity Antiferromagnetism Spin glass