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2018.06.12 jairo sinova jgu

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II Jornada científica NanoFrontMag - 12 de junio de 2018 - IMDEA Nanociencia
Jairo Sinova
Johannes Gutenberg Universität Mainz

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2018.06.12 jairo sinova jgu

  1. 1. !1Nano-front Magnetism —Madrid — Jairo Sinova 12th of June 2018 Jairo Sinova Johannes Gutenberg Universität Mainz Smejkal, Zelezny, Sinova, Junwirth PRL (2017) Smejkal, Jungwirth, Sinova PSS (2017) Jairo Sinova and Tomas Jungwirth, Physics Today (2017) Bodar, Smejkal, Jourdan, Kläui, JS, et al, Nature Comm. (2018) Jungwirth, JS, et al, Nature Physics (AFM spintronics Reviews) (2018) Topological Antiferromagnetic Spin-orbitronics: from spin Hall effect, to spin-orbit torques, to Néel spin-orbit torques, to tunable Dirac fermions Olejnik, Jugwirth, Kampfrad, JS, et al - Science Advance 2018
  2. 2. !2Nano-front Magnetism —Madrid — Jairo Sinova I. Spin-Orbit Torques in Ferromagnets and Antiferromagnets: •SHE and Inverse spin galvanic effect phenomenology •Spin-orbit Torques •Néel Spin-orbit Torque II.Topological Dirac Fermion + Antiferromagnets + Neel SOTs III.AHE in collinear AFMs Kurebayashi, et al., Nat. Nanot. (2014) Zelezny, Gao, JS, Jungwirth PRL (2014) Zelazny, Gao, et al. PRB (2016) Gomonay, Jungwirth, Sinova PRL (2016) Yu, Smejkal, Jourdan, Kläui, JS, et al, arXiv: 1706.02482 (2017) Sinova,et al RMP (2015) Smejkal, Zelezny, Sinova, Junwirth PRL (2017) Smejkal, Jungwirth, Sinova PSS (2017) Ciccarelli, et al., Nat. Phys. (2016) Olejnik, Jugwirth, Kampfrad, JS, et al - Science Advance 2018 Topological Antiferromagnetic Spin-orbitronics: from spin Hall effect, to spin-orbit torques, to Néel spin-orbit torques, to tunable Dirac fermions Surprises of the Spin Hall Effect, Physics Today 70, 7, 38 (2017) Jungwirth, JS, et al, Nature Physics (AFM spintronics Reviews) (2018)
  3. 3. !3 Hilbert et al. Science (2011) Analog to Digital Gutenberg (1400-1468) 1015 1014 1013 1012 1986 1993 2000 2007 Digital: Hard-disks, DVDs,… Analog: books, video/film, … MB Analog to digital = Ink to Spin Nano-front Magnetism —Madrid — Jairo Sinova
  4. 4. Discovery of Giant Magneto Resistance !4Nano-front Magnetism —Madrid — Jairo Sinova Albert Fert Peter Grünberg GMR first observed in 1988 From fundamental to practical Stuart Parkin 2014 Humboldt Professor and 2014 Millennium Prize Low Resistance High Resistance
  5. 5. What is next in memory storage? !5Nano-front Magnetism —Madrid — Jairo Sinova Spin-Transfer MRAM (2015) Heating Problems MRAM Magnetic Random Access Memory First generation did NOT combine charge and spin
  6. 6. Magnetization dynamics and Spin Transfer Torque !6Nano-front Magnetism —Madrid — Jairo Sinova d ˆM dt = ˆM ⇥ ~Heff + ↵ ˆM ⇥ d ˆM dt + ~PJ 2e ( ˆM ⇥ ˆM0) ⇥ ˆM (proposed by Slonczewski, Berger 1996) Ferro 1 Ferro 2Spacer Torque Spin Transfer Torque
  7. 7. Spin-Transfer-Torque MRAM !7Nano-front Magnetism —Madrid — Jairo Sinova Spin-Transfer-Torque MRAM MTJ STT mechanism: ~ 30 μA • excellent scaling • lower power • no crosstalk problem • simpler fabrication 3"
  8. 8. in-plane-current switching MRAM !8Nano-front Magnetism —Madrid — Jairo Sinova MTJ In-plane-current-switching MRAM If switching can be done by an in-plane current then a key issue in STT-MRAM is resolved 4"
  9. 9. Control of materials properties via spin-orbit coupling Antiferro magnetic materials Nano- transport Spintronic Hall effects Topological transport effects Spin- orbitronics Caloritronics Spin-orbit Torques !9Nano-front Magnetism —Madrid — Jairo Sinova Spin-orbitronics
  10. 10. Inverse Spin Galvanic Effect or Edelstein Effect !10Nano-front Magnetism —Madrid — Jairo Sinova Spin-current and spin-polarization generation by currents (Reverse process of circular photo-galvanic effect, Ganichev et al., 2001) Wunderlich et at. arXiv ‘04, PRL ‘05 Spin Hall Effect in p-GaAs
  11. 11. [100] [010] Intrinsic spin-Hall effect: the Rashba SOC example +sz -sz ~Beff (~k) / ~seq Δp ∼ eEt ~E Beff ⇠ pˆy ~E ky [010] kx [100] S=0 HR = ~2 k2 2m µB~ · ~Beff (~k) = ~2 k2 2m + ↵R( xky ykx) !11Nano-front Magnetism —Madrid — Jairo Sinova
  12. 12. Inverse Spin Galvanic Effect or Edelstein Effect !12Nano-front Magnetism —Madrid — Jairo Sinova kx ky δS=0δSy≠0 J || x Wunderlich, Jungwirth, JS, et al PRL/PRB 2003/2004 Current induced polarization
  13. 13. Experiments of in-plane current magnetic switching Miron et al., Nature ‘11 Buhrman,et al., Science ‘12 !13Nano-front Magnetism —Madrid — Jairo Sinova spin-orbit torque at PM/FM interface intrinsic SHE + STT SHE as spin-current generator + STT d ~M dt ! SHE ST T = P ˆM ⇥ (ˆn ⇥ ˆM) d ~M dt ! SOT = Jex ~ ~M ⇥ ~s hSOT || z × J Jairo Sinova and Tomas Jungwirth, Physics Today (2017)
  14. 14. !14Nano-front Magnetism —Madrid — Jairo Sinova SpinHall Rashba Courtesy of P. Gambardella Spin-orbit Torques in Bilayer Systems Make a ferromagnet behave like a cat: SOC (broken bulk inversion)+ferromagnetism ?
  15. 15. [100] [110] [010] [100] [110] [010] Dresselhaus GaMnAs GaAs GaMnAs Intrinsic (Berry phase) spin-orbit torque in GaMnAs !15Nano-front Magnetism —Madrid — Jairo Sinova Rashba d ˆM dt ! SOT = ˆM ⇥ sz(✓M E)ˆz current direction angle between M and current direction Kurebayashi, JS, et al., Nat. Nanot. (2014)
  16. 16. !16Nano-front Magnetism —Madrid — Jairo Sinova 90 180 270 -150 -100 -50 0 50 100 150 µ0 hz [µT] [100] 90 180 270 -150 -100 -50 0 50 100 150 [010] 0 90 180 270 360 θM-J -150 -100 -50 0 50 100 150 µ0 hz [µT] [1-10] 90 180 270 360 θM-J -150 -100 -50 0 50 100 150 [110] Discovery of anti-damping spin-orbit torques Solid line: Calculations with HKL (captures higher harmonics) S // M [100] [010] Kurebayashi, JS, et al., Nat. Nanot. (2014)
  17. 17. Antiferromagnetic Spintronics 17Nano-front Magnetism —Madrid — Jairo Sinova Spin not charge based Radiation-hard Ordered spins Non-volatile No net moment Insensitive to magnetic fields, no fringing stray fields THz dynamics Ultra-fast switching Multiple-stable domain configurations Memory-logic bit cells Materials range Insulators, semiconductors, semimetals, metals, superconductors Last issue of the International Technological Roadmap for Semiconductors in 2016
  18. 18. !18Nano-front Magnetism —Madrid — Jairo Sinova Writing by spin-orbit torque in a single-layer ferromagnet Magnet reversing itself : SOT Antiferromagnetic Spin-orbitronics AFM Néel SOT J. Zelezny, H. Gao, K. Vyborny, J. Masek, J. Zemen, A. Manchon, J. Sinova, and T. Jungwirth, PRL (2014)
  19. 19. !19Nano-front Magnetism —Madrid — Jairo Sinova Antiferromagnet with broken sublattice space-inversion symmetry: (Mn2Au) Writing by Néel spin-orbit torque in a single-layer antiferromagnet kx ky kx ky S=0 S=0 Sy≠0 Sy≠0 J || x HSOT || z × J HSOT || -z × J Zelezny, Gao, Jungwirth, JS PRL 2004
  20. 20. !20Nano-front Magnetism —Madrid — Jairo Sinova Antiferromagnet with broken sublattice space-inversion symmetry: (Mn2Au) By A By B Bx B Bx A 0 45 90 135 180 Φ (Degrees) B(mT)(per107A/cm2) 0.4 0.2 0 -0.2 -0.4 -90 -45 0 45 90 θ (Degrees) B(mT)(per107A/cm2) 0.3 0.1 0 -0.1 -0.3 Bx A Bx B By B Bz B By A Bz A J || x Zelezny, Gao, Jungwirth, JS December PRL (2014) Writing by Néel spin-orbit torque in a single-layer antiferromagnet
  21. 21. !21 How it works - kind of Nano-front Magnetism —Madrid — Jairo Sinova
  22. 22. Experimental Observation of Néel SOT in CuMnAs !22Nano-front Magnetism —Madrid — Jairo Sinova0.4 0.8 !0.05 0.00 0.05 ( /cm 3 ) ( ( 20 40 4.4)kO e)applied)No)field)applied !30 0 30 $ $ $ ΔRt (mΩ) 0 20 40 60 80 100 120 140 160 !30 0 30 $P uls e$number $ $ ΔRt (mΩ) A" B" C" D" 5 6 7 8 9 10 0 10 20 30 40 + + ΔRt+ (mΩ) S etting+current+dens ity+(MA/cm 2 ) A" B" 1" 2" 3" 4"5"6" 7" 8"CuMnAs" GaP" C" D" 0 2 4 6 8 10 '10 0 10 ( ( ΔRt ((mΩ) P uls e(number 0 2 4 6 8 10 '10 0 10 ( (ΔRt ((mΩ) ( P uls e(number !0 !0 0 0 0 Moment((emu/cm 3 ) 0 2 4 6 8 10 12 '40 '20 0 20 40 4.4)kO e)applied ) ) ΔRt (mΩ) P uls e)number No)field)applied 0 20 40 60 80 100 120 140 160 !30 $P uls e$number Figure"4"" (A)"Transverse"resistance"using"orthogonal"probe"curren (black)"and"3H7"(red)."(B)"Dependence"of"the"change"in"t density"of"the"seUng"pulse."The"dashed"line"is"a"guide"to resistance"aFer"current"pulses"alternately"along"orthogo 1H6)"and"with"4.4"kOe"field"applied"(pulses"7H12)."(D)"Ma measured"by"SQUID"magnetometer." " C" D" 5 0 Setting 1-5 Setting 3-7 CuMnAs A B Rashba field: B ~ 3 mT per 107 Acm-2 Wadley, Jungwirth, et al Science (2016) AMR correspondance to Neel switching verified by X-ray MLD photoemission electron microscopy
  23. 23. From prediction, to observation, to device in 1 one year!! !23Nano-front Magnetism —Madrid — Jairo Sinova Works like this but not done like this Electrical read/write antiferromagnetic memory Wadley, Jungwirth et al. Science ’16, Jungwirth, Marti, Wadley, Wunderlich, Nature Nanotech. ’16
  24. 24. Experimental Observation of Néel SOT in Mn2Au !24Nano-front Magnetism —Madrid — Jairo Sinova ● ● ● ● ● ■ ■ ■ ■ ■ ● Mn-Au ■ Au 0 1 2 3 4 5 0 10 20 30 Disorder/% ρ/μΩcm ■ ■ ■ ■ □ □ □ □ □ ● ● ● ● ● ○ ○ ○ ○ ○ ■ Au [100] □ Au [110] ● Mn-Au [100] ○ Mn-Au [110] 0 1 2 3 4 5 0 1 2 3 4 5 6 Disorder/% AMR/% [100] [010] [001] Experiment Experiment 0.6+-0.3% Au rich, Mn-Au <5% Experiment: S.Bodnar et al.*, (2.5-6 %), M.Meinert et al, arXiv.1706.06983 (5 %D: App.Phys) M.Jourdan et al., JoP . (2015): 8 μΩcm H.Wu et al., AFM (2016) (1-2.5 %) Relativistic DFT: Bodnar, Smejkal, Jourdan, Kläui, Jungwirth, JS, et al, Nature Communications (2018)
  25. 25. Anisotropic spectral function and stability of Dirac points !25Nano-front Magnetism —Madrid — Jairo Sinova CPA preserves the symmetry prevented hybridisations Disorder propagates Dirac point to Fermi level and shifts the Fermi level E(k) ! A(E, k) = 1 ⇡ ImG kx -1.5 -1 -0.5 0 0.5 Energy/eV M Γ [100] [010] Angular dependence of Bloch spectral function ⇢k > ⇢? AMR > 0 n||[010]n||[100] ⇢? ⇢k -1.5 -1 -0.5 0 0.5 Energy/eV M Γ [100] [010] Bodnar, Smejkal, Jourdan, Kläui, Jungwirth, JS, et al, Nature Communications (2018)
  26. 26. !26Nano-front Magnetism —Madrid — Jairo Sinova CuMnAs THz writing speed 𝟏/𝝉 𝒑 in antiferromagnetic memory CuMnAs 2μm THz writing speed !/#$ in antiferromagnetic memory Contact μs-pulse electrical writing Non-contact ps-pulse electrical writing E 1/'( ≈ MHz 1/'( ≈ THz Olejnik, TJ et al., unpubl. Olejnik, Jungwirth, Kampfrad, JS, et al - Science Advance 2018
  27. 27. 27Nano-front Magnetism —Madrid — Jairo Sinova THz writing speed 𝟏/𝝉 𝒑 in antiferromagnetic memory Non-contact electrical writing with 1/#$ = THz pulses THz writing speed */+, in antiferromagnetic memory Transverse AMR readout V V V V Contact electrical writing with 1/#$ = MHz pulses Olejnik, TJ et al., unpubl. !~10% Acm*+ @ 1/./~ GHz Olejnik, Jungwirth, Kampfrad, JS, et al - Science Advance 2018
  28. 28. !28Nano-front Magnetism —Madrid — Jairo Sinova I. Spin-Orbit Torques in Ferromagnets and Antiferromagnets: •SHE and Inverse spin galvanic effect phenomenology •Spin-orbit Torques •Néel Spin-orbit Torque II.Topological Dirac Fermion + Antiferromagnets + Neel SOTs III.AHE in collinear AFMs Kurebayashi, et al., Nat. Nanot. (2014) Zelezny, Gao, JS, Jungwirth PRL (2014) Zelazny, Gao, et al. PRB (2016) Gomonay, Jungwirth, Sinova PRL (2016) Yu, Smejkal, Jourdan, Kläui, JS, et al, arXiv: 1706.02482 (2017) Sinova,et al RMP (2015) Smejkal, Zelezny, Sinova, Junwirth PRL (2017) Smejkal, Jungwirth, Sinova PSS (2017) Ciccarelli, et al., Nat. Phys. (2016) Olejnik, Jugwirth, Kampfrad, JS, et al - Science Advance 2018 Topological Antiferromagnetic Spintronics: from spin Hall effect, to spin-orbit torques, to Néel spin-orbit torques, to tunable Dirac fermions Surprises of the Spin Hall Effect, Physics Today 70, 7, 38 (2017) Jungwirth, JS, et al, Nature Physics (AFM spintronics Reviews) (2018)
  29. 29. !29Nano-front Magnetism —Madrid — Jairo Sinova 2003 2017 SHE QSHE 2D TI graphene SOT 3D TI Dirac/Weyl semimetals Néel SOT
  30. 30. Coexistence of Topological Dirac fermions and Néel !30Nano-front Magnetism —Madrid — Jairo Sinova Can we control the relativistic fermions electrically? ? + Smejkal, Zelezny, Sinova, Jungwirth PRL (2017)
  31. 31. 31Nano-front Magnetism —Madrid — Jairo Sinova Model of AFM topological semimetal [001] δs A δs BA B [100] [010] J YES! Overlap of symmetry conditions Dirac fermions AF spintronics ? + 1. Two sites in unit cell band crossing inversion-partner sites → staggered field PT2. symmetry Double band degeneracy → Dirac point AF spin-sublattices at inversion partner sites
  32. 32. Minimal lattice model: construction !32Nano-front Magnetism —Madrid — Jairo Sinova Smejkal, Zelezny, Sinova, Jungwirth PRL (2017) Kane-Mele spin-orbit coupling A B A B
  33. 33. Minimal lattice model: band structure !33Nano-front Magnetism —Madrid — Jairo Sinova Smejkal, Zelezny, Sinova, Jungwirth PRL (2017) Renormalization: 2D Dirac points —> 3D nodal lines D2D1
  34. 34. Minimal lattice model: local symmetries !34Nano-front Magnetism —Madrid — Jairo Sinova P PT + A, B noncentrosymmetric P Neel spin-orbit torque z x Pseudovector/axial vector PT Smejkal, Jungwirth, Sinova PSS (2017)
  35. 35. Symmetry protection of Dirac points !35Nano-front Magnetism —Madrid — Jairo Sinova [100] [010] Mirror Translate nonsymmorphic symmetry = point group + nontrivial translation glide mirror plane Gx={Mx/(1/2,0,0)} Mx at Gx invariant subspace
  36. 36. !36Nano-front Magnetism —Madrid — Jairo Sinova Electrical control of Dirac fermions Nonsymmorphic symmetry: Screw axis+Glide plane Demonstration of inplane Field like torque manipulation Demonstration of (001) ! inplane Field like torque tetra. ortho.
  37. 37. Topological magnetotransport: AMR !37Nano-front Magnetism —Madrid — Jairo Sinova
  38. 38. !38Nano-front Magnetism —Madrid — Jairo Sinova Néel SOT in a single- layer antiferromagnet SUMMARY SOT in a single-layer ferromagnet M MB −~eq eff Beff ⇠ pˆy ~E Kurebayashi, et al., Nature Nanotech (2014) JS,Valenzuela, Wunderlich, Back, Jungwirth RMP (2015) SHE and ISGE Wadley, et al Science (2016) Neel SOT physics (ii)Topological Dirac Semi Metal+ AFM (i) Topological Antiferromagnetic Spin-orbitronics Kurebayashi, et al., Nature Physics (2016) Libor Smejkal, et al PRL (2017) and PSS (2017) J. Zelezny, et al, PRL (2014) J. Zelezny, et al, PRB (2016) O. Gomonay, et al, PRL (2016) Yu, et al. arXiv: 1706.02482 (2017) Jungwirth, JS, et al, Nature Physics (AFM spintronics Reviews) (2018) AHE in RuO2 (col-AFM)(iii)
  39. 39. !39Nano-front Magnetism —Madrid — Jairo Sinova Smejkal, Zelezny, Gyles, Ciccarelli, Kläui, Gomonay, Wadley, Kampfrath, Jungwirth Univ. of NottinghamInstitute of Physics Prague Univ. of Cambridge MPI - Berlin
  40. 40. 40 3rd-7th of September 2018 - Mainz, Germany 9th JEMS Conference 2018 Joint European Magnetic Symposia

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