Anisotropic magnetoresistance effects in Anisotropic magnetoresistance effects in ferromagnetic semiconductor and metal devices ferromagnetic semiconductor and metal devices Tomas Jungwirth University of Nottingham Bryan Gallagher, Tom Foxon, Richard Campion, Kevin Edmond Andrew Rushforth, Chris King et Hitachi Labs., UK & Japan University of Texas and Texas A&M Jorg Wunderlich, Byong-Guk Park, Andrew Irvine, Allan MacDonald, Jairo Sinova David Williams, Akira, Sugawara, et al. Institute of Physics ASCR exander Shick, Jan Mašek, Josef Kudrnovský, antišek Máca, Karel Výborný, Jan Zemen, Vít Novák, Kamil Olejník, et al. University of Wuerzburg Polish Academy of Sciences Tohoku University Laurens Molenkamp, Charles Gould Tomasz Dietl, et al. Hideo Ohno, et al.
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Anisotropic magnetoresistance effects in ferromagnetic semiconductor and metal devices Tomas Jungwirth University of Nottingham Bryan Gallagher, Tom Foxon,
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Anisotropic magnetoresistance effects in ferromagnetic Anisotropic magnetoresistance effects in ferromagnetic semiconductor and metal devicessemiconductor and metal devices
Tomas Jungwirth
University of Nottingham Bryan Gallagher, Tom Foxon,
Richard Campion, Kevin Edmonds, Andrew Rushforth, Chris King et al.
Hitachi Labs., UK & Japan University of Texas and Texas A&M Jorg Wunderlich, Byong-Guk Park, Andrew Irvine, Allan MacDonald, Jairo Sinova David Williams, Akira, Sugawara, et al.
Institute of Physics ASCR Alexander Shick, Jan Mašek, Josef Kudrnovský,
František Máca, Karel Výborný, Jan Zemen, Vít Novák, Kamil Olejník, et al.
University of Wuerzburg Polish Academy of Sciences Tohoku University Laurens Molenkamp, Charles Gould Tomasz Dietl, et al. Hideo Ohno, et al.
Outline
1. Intro - basic micromagnetics in DMSs
2. DMS materials science
3. AMR effects in DMSs and metals – devices and physics
(Ga,Mn)As: an archetypical dilute moment FM semiconductor
Mn-d-like localmoments
As-p-like holes
Mn
Ga
AsMn
SW-transf. Jpd SMn . shole
Dilute Mn-doped SC: sensitive to doping; 100smaller Ms than in conventional metal FMs
Mn-Mn coupling mediated by holes in SO-coupled SC valence bands:sensitive to gating, comparable magnetocrystalline anisotropy energy and stiffness to metal FMs
For not too strong p-d hybridization:kinetic-exchange (Jpd) & host SC bands provides simple yet often semiquantitative description
MF-like M(T);square hysteresis loops
1 mm 500 nm
8 K 22 KMacro (100’s m) domains;
10-100 nm domain walls (~A/K)reflecting combined T-dependentuniaxial and cubic anisotropies