2010

Signatures of asymmetric and inelastic tunneling on the spin torque bias dependence

Signatures of asymmetric and inelastic tunneling on the spin torque bias dependence
A. Manchon, S. Zhang, and K.-J. Lee
Phys. Rev. B 82, 174420 (2010)​​​​​​​​​​​​
A. Manchon, S. Zhang, K.-J. Lee
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2010
The influence of structural asymmetries (barrier height and exchange splitting), as well as inelastic scattering (magnons and phonons) on the bias dependence of the spin transfer torque in a magnetic tunnel junction is studied theoretically using the free-electron model. We show that they modify the “conventional” bias dependence of the spin transfer torque, together with the bias dependence of the conductance. In particular, both structural asymmetries and bulk (inelastic) scattering add antisymmetric terms to the perpendicular torque (V and je|V|) while the interfacial inelastic scattering conserves the junction symmetry and only produces symmetricterms (|V|nnN). The analysis of spin torque and conductance measurements displays a signature revealing the origin (asymmetry or inelastic scattering) of the discrepancy.