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

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Presentation on theme: "Spintronics: How spin can act on charge carriers and vice versa Tomas Jungwirth University of Nottingham Institute of Physics Prague."— Presentation transcript:

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

2

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

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

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

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

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

8 Fixed FM AFM FM Toggle switching first commercial MRAMs Synthetic AFM

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

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

11 MRAM: universal memoryCompatible with CMOS GB MRAMs in few years

12 Conventional architecture with CMOSNew architectuture with MRAM kB MB GB TB huge gap

13 Worldwide MRAM development

14 Spin-transistor Datta, Das, APL 1990

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

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

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

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

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

20 Spin-orbit coupling nucleus rest frame electron rest frame Lorentz transformation Thomas precession 22

21 Spin-orbit coupling: quantum relativistic physics

22 Dirac equation

23 Spin-orbit coupling: quantum relativistic physics

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

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

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

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

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

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

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

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

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

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

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

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

36 Inverted approach to spin-transistorDirect approach to spin-transistor

37 Inverted approach to spin-transistorDirect approach to spin-transistor

38 Inverted approach to spin-transistorDirect approach to spin-transistor

39 Inverted approach to spin-transistorDirect approach to spin-transistor

40 Inverted approach to spin-transistorDirect approach to spin-transistor


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