1. Spintronics: How spin can act on charge carriers and vice versa
Tomas Jungwirth
University of Nottingham
Institute of Physics Prague

3. Reading by GMR (TMR) Writing by STT STT-MRAM
Fert, Grünberg, et al. 1988
Nobel Prize 2007
Sloncyewski, Berger, 1996
Buckley Prize at APS MM 2013

4. Read-out: non-relativistic giant magnetoresistance (GMR)Ie Ie
Fert, Grünberg, et al. 1988
Nobel Prize 2007

5. Read-out: non-relativistic giant magnetoresistance (GMR)
Fert, Grünberg, et al. 1988
Nobel Prize 2007
Antiferromagnetic arrangement of a ferromagnetic multilayer at B=0

6. Writing information in spin-valve: towards spintronic memory (MRAM)
1. AFM coupling between FMs at B=0 FM FM FM
2. One FM flips harder than the other FM
Soft FM
Hard FM
Soft FM
Hard FM
3. One FM pinned by AFM material
Fixed FM
AFM
Soft FM
Fixed FM
AFM
Soft FM

7. Towards reliable switching of a particular MRAM bit
Fixed FM NM
AFM
Soft FM

8. Toggle switching  first commercial MRAMsFM
“Synthetic AFM“ FM
Fixed FM
AFM

9. Writing by current: non-relativistic spin-transfer torque (STT)
Spins injected from external polarizer in a non-uniform magnetic structure Mp M Ie
Sloncyewski, Berger, 1996
Buckley Prize at APS MM 2013

10. MRAM: universal memory
Write with magnetic field:
on market since 2006
scales with current
Write with current (STT-MRAM):
on market since 2013
scales with current density

11. MRAM: universal memory
Compatible with CMOS
GB MRAMs in few years

12. Conventional architecture with CMOS New architectuture with MRAMkB MB GB
huge
gap TB

13. Worldwide MRAM development

14. Spin-transistor
Datta, Das, APL 1990

15. Conventional architecture with CMOS
New architectuture with spin-memory/logic

16. Read-out: non-relativistic giant magnetoresistance (GMR)Ie Ie
Fert, Grünberg, et al. 1988
Nobel Prize 2007

17. Read-out: relativistic anisotropic magnetoresistance (AMR)
Spintronic effect 150 years ahead of time M Ie
Kelvin, 1857

18. Read-out: relativistic anisotropic magnetoresistance (AMR)
Spintronic effect 150 years ahead of time M Ie
Kelvin, 1857

19. Two paradigms for spintronics
“Mott“ non-relativistic two-spin-channel model of ferromagnets I I
Mott, 1936
“Dirac“ relativistic spin-orbit coupling I I
Dirac, 1928

20. 2 2 Spin-orbit coupling nucleus rest frame electron rest frame
Lorentz transformation  Thomas precession

21. Spin-orbit coupling: quantum relativistic physics

22. Spin-orbit coupling: quantum relativistic physics
Dirac equation

23. Spin-orbit coupling: quantum relativistic physics

24.  Ultra-relativistic quantum particles (neutrino) Dirac equation
spin and orbital motion coupled 

25.  Ultra-relativistic quantum particles (neutrino) Dirac equation
spin and orbital motion coupled 

26.   Ultra-relativistic quantum particles (neutrino) Dirac equation
spin and orbital motion coupled  

27. Ohmic “Dirac“ device: AMR
Kelvin, 1857
Magnetization-orientation-dependent scattering

28. Ohmic “Mott“ device: GMR
Fert, Grünberg, 1988
Spin-channel-dependent scattering

29. Tunneling “Mott“ device: TMR
Julliere 1975, Moodera et al., Miyazaki & Tezuka 1995
MRAM
Spin-channel-dependent tunneling DOS

30. Tunneling “Dirac“ device: TAMR
Gould, TJ et al. PRL ‘04
Magnetization-orientation-dependent
tunneling DOS

31.  Magnetization-orientation-dependent chemical potential
Chemical potential controlled “Dirac“ device
Wunderlich, TJ et al. PRL ‘06

32.  Magnet Dielectric M Non-magnetic channel I I
Dirac spintronic device without current through magnet  I I
Chemical potential of magnetic gate changes
Charge on magnetic gate changes
Polarisation charge on non-magnetic channel 
Magnet - +
Dielectric - + M
Non-magnetic
channel
Ciccarelli, Ferguson, TJ et al. APL ‘12

33.  Magnet Dielectric M Non-magnetic channel I I
Dirac spintronic device without current through magnet  I I
Chemical potential of magnetic gate changes
Charge on magnetic gate changes
Polarisation charge on non-magnetic channel 
Magnet - +
Dielectric - + M
Non-magnetic
channel
Ciccarelli, Ferguson, TJ et al. APL ‘12

34.  Magnet Dielectric M Non-magnetic channel I I
Dirac spintronic device without current through magnet  I I
Chemical potential of magnetic gate changes
Charge on magnetic gate changes
Polarisation charge on non-magnetic channel 
Magnet - +
Dielectric - + M - +
Non-magnetic
channel - + - +
Ciccarelli, Ferguson, TJ et al. APL ‘12

35. DVg = Dm/e Dirac spintronic device without current through magnet
Ciccarelli, Ferguson, TJ et al. APL ‘12

36. Direct approach to spin-transistor
Inverted approach to spin-transistor

37. Direct approach to spin-transistor
Inverted approach to spin-transistor

38. Direct approach to spin-transistor
Inverted approach to spin-transistor

39. Direct approach to spin-transistor
Inverted approach to spin-transistor

40. Direct approach to spin-transistor
Inverted approach to spin-transistor