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Spintronics: How spin can act on charge carriers and vice versa

Spintronics: How spin can act on charge carriers and vice versa. Tom as Jungwirth. University of Nottingham. Institute of Physics Prague. . Mott with spin current . Mott with out spin current . ‪ Spintronics ‬ From Wikipedia, the free encyclopedia

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Spintronics: How spin can act on charge carriers and vice versa

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  1. Spintronics: How spin can act on charge carriers and vice versa TomasJungwirth Universityof Nottingham Institute of Physics Prague

  2. Mott with spin current Mott withoutspin current ‪Spintronics ‬From Wikipedia, the free encyclopedia Spintronics (a pormanteau meaning spin transport electronics).... I I GMR 1988 MRAM 2006 Dirac withoutcurrent through magnet Dirac with current through magnet I AMR 1857 HD Read-heads 1990‘s I I I

  3. Mott with ferromagnets  Mott with antiferromagnets I I I I Dirac with ferromagnets Dirac with antiferromagnets I I I I

  4. Control by current via spin torques: scales with current density 0.1 pJ Control by photo-carriers via spin torques: sub ps timescales Magnetic-field control of FMs: scales with current Laser Relativistic spin-orbit torques might work equally well in AFMs plus photocarriers in SCs Electro-static field control via relativistic magnetic anisotropy effects: 1fJ Should work equally well or better in AFMs: more choices including SCs (or piezo-electric)

  5. Writing by current via spin torques: scales with current density 0.1 pJ Writing by photo-carriers via spin torques: sub ps timescales Laser Relativistic spin-orbit torques might work equally well in AFMs plus photocarriers in SCs

  6. Optical spin-transfer torque OSTT s Pn Pn M M s M M   Němec, Tesařová, Novák, TJ et al. Nature Phys.’12, Nature Photonics ‘13, Nature Commun. ‘13 Fernandez-Rossier, Nunez, Abofath, MacDonald cont-mat/0304492

  7. Optical spin-transfer torque OSTT s Pn  Pn M M s Němec, Tesařová, Novák, TJ et al. Nature Phys.’12, Nature Photonics ‘13, Nature Commun. ‘13 Fernandez-Rossier, Nunez, Abofath, MacDonald cont-mat/0304492

  8. Optical spin-transfer torque OSTT s Pn  Pn M M s Němec, Tesařová, Novák, TJ et al. Nature Phys.’12, Nature Photonics ‘13, Nature Commun. ‘13 Fernandez-Rossier, Nunez, Abofath, MacDonald cont-mat/0304492

  9. Electrical spin-transfer torque Antidamping-like (adiabatic) STT OSTT Pn M s Zhang and Li PRL 2004 Vanhaverbeke et al. PRB 2007,......

  10. Electrical spin-transfer torque Field-like (non-adiabatic) STT s Pn M Zhang and Li PRL 2004 Vanhaverbeke et al. PRB 2007,......

  11. Electrical spin-transfer torque Antidamping-like STT Field-like STT ~ small  in weakly SO-coupled dense-momentmetal FMs large  in strongly SO-coupled dilute-moment (Ga,Mn)As

  12. Electrical spin-transfer torque: current induced DW motion

  13. Electrical spin-transfer torque: current induced DW motion vDW  = 0 “intrinsic” pinning j  jC Antidamping STT Antidamping-like STT Zhang & Li, PRL 93, 127204 (2004) Vanhaverbeke & Viret, PRB 75, 024411 (2007)

  14. Electrical spin-transfer torque: current induced DW motion vDW  <  j  jC Antidamping STT Antidamping-like STT Zhang & Li, PRL 93, 127204 (2004) Vanhaverbeke & Viret, PRB 75, 024411 (2007) Field-like STT

  15. Electrical spin-transfer torque: current induced DW motion vDW  >   <  j  jC jC Antidamping STT Antidamping-like STT Zhang & Li, PRL 93, 127204 (2004) Vanhaverbeke & Viret, PRB 75, 024411 (2007) Field-like STT

  16. Steady-state carrier spin polarization  torque QM averaging in non-equilibrium Electrical spin injection Non-relativistic STT Steady state Optical spin injection External OSTT antidamping-like torque M

  17. Steady-state carrier spin polarization  torque QM averaging in non-equilibrium Electrical spin injection Relativistic SOT Internal Steady state Optical spin injection (Ga,Mn)As OSOT M

  18. Steady-state carrier spin polarization  torque Linear response: eigenstates of H & non-equilibrium distribution Electrical drift and relaxation: broken inversion symmetry Relativistic SOT Internal Steady state Optical generation and relaxation

  19. Paramagnets Spin-orbit Magnetic field of moving nucleus in electron‘srest frame Spin-galvanic effect = SOT without acting on Electrical drift and relaxation: broken inversion symmetry Aronov, Lyanda-Geller, JETP ’89, Edelstein SSC ’90, Ganichev et al. Nature ‘02

  20. Paramagnets Spin-orbit Magnetic field of moving nucleus in electron‘srest frame Spin Hall effect

  21. MRAM switching by in-plane current  SHE spin-current  non-relativistic STT Ralph, Buhrman,et al., Science ‘12 Hall antidamping STT SHE in Pt acts as the external polarizer

  22. MRAM switching by in-plane current  attractive alternative to perp. current STT Conventional perpendicular current STT

  23. MRAM switching by in-plane current  attractive alternative to perp. current STT Conventional perpendicular current STT

  24. Competing scenario: In-plane current swithing by relativitic SOT due to broken structural inversion symmetry at Co/Pt? Miron et al., Nature ‘11

  25. Ralph, Buhrman et al.: SHE Miron et al.: SOT -We see antidamping-like torque -SOT is field-like so we exclude it - non-relativistic STT in metals is dominated by the antidamping torque -We also see antidamping-like torque -SOT is field-like but maybe there is some antidamping-like SOT as well

  26. Where could a comparable strength antidamping-like SOT come from?

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