Research fueled by:

Frontiers in Materials: SpintronicsStrasboug, France

May 13th, 2012

Expecting the unexpected in the spin Hall effect:

from fundamental to practical

JAIRO SINOVA Vivek Amin

Texas A&M UniversityInstitute of Physics ASCR

Hitachi CambridgeJoerg Wünderlich, A. Irvine, et al

Institute of Physics ASCRTomas Jungwirth, Vít Novák, Karel Vyborny, et al

Expecting the unexpected in the spin Hall effect: from fundamental to practical! The spin Hall effects is a relativistic spin-orbit coupling phenomenon which can be used to electrically generate or detect spin currents in magnetic and non-magnetic systems. In spite of the short time since its discovery it has now become ubiquitous in the field of spintronics and its development has also sparked a renewed interest in the full understanding of all the relating effects, such as the anomalous Hall effect. Exploiting such effects fully requires a better understanding of the effects and their intricate connections. SHE has been used to create one of the first spin FETs, to measure spin-currents generated by magnetization dynamics, and even to generate spin-currents large enough to produce spin-torque effects! In this talk I attempt to give a short, brief, and possibly oversimplified overview of some of the critical developments of this vibrant subfield of spintronics, its present understanding, its present applications, and some of its future challenges.

3Nanoelectronics, spintronics, and materials control by spin-orbit coupling

I. Introduction:•Basic AHE and SHE phenomenology•Mechanism

II. Spin Hall effect: the early days I.First proposals: from theory to experimentII.First observations of the extrinsic and intrinsic (optical)

III. Inverse spin Hall effect•Direct iSHE in metals•Spin pumping and FMR

IV.SHE-FET•Spin Hall injection and spin precession manipulation•iSHE device with spin-accumulation modulation

V. SHE as a spin current generator and detector•Spin based FET: old and new paradigm in charge-spin transport•Theory expectations and modeling•Experimental results

VI.Conclusion

Expecting the unexpected in the spin Hall effect:

from fundamental to practical

4Nanoelectronics, spintronics, and materials control by spin-orbit coupling

The electron: the key character with dual personalities

CHARGECHARGEEasy to manipulate: Coulomb interaction

SPIN 1/2SPIN 1/2Makes the electron antisocial: a fermion

quantum mechanics

E=p2/2mE→ iħ d/dtp→ -iħ d/dr

““Classical” external manipulation of charge & spinClassical” external manipulation of charge & spin

special relativity

E2/c2=p2+m2c2

(E=mc2 for p=0)

+ particles/antiparticles & spin

Dirac equation=

5Nanoelectronics, spintronics, and materials control by spin-orbit coupling

Using charge and spin in information technology

HIGH tunablity of electronic transportproperties the key to FET success in processing technology

substrate

semiconductor

insulatorS Dgate

Vg >0

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