Anatomy of Spin-Transfer Torque

Published

July 1, 2002

Author(s)

Mark D. Stiles, A Zangwill

Abstract

Spin-transfer torques occur in magnetic heterostructures because the transverse component of a spin current that flows from a non-magnet into a ferromagnet is absorbed at the interface. We demonstrate this fact explicitly using free electron models and first principles electronic structure calculations for real material interfaces. Three distinct processes contribute to the absorption: (1) spin-dependent reflection and transmission; (2) rotation of reflected and transmitted spins; and (3) spatial precession of spins in the ferromagnet. When summed over all Fermi surface electrons, these processes reduce the transverse component of the transmitted and reflected spin currents to nearly zero for most systems of interest. Therefore, to a good approximation, the torque on the magnetization is proportional to the transverse piece of the incoming spin current.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Volume

66

Issue

014407

Pub Type

Journals

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Keywords

angular momentum transfer, current-induced torque, interface electronic structure, Magnetic multiplayer, precession, reflection, spin current spin-dependent, spin-transfer, transverse-spin-current decay

Citation

Stiles, M. and Zangwill, A. (2002), Anatomy of Spin-Transfer Torque, Physical Review B (Condensed Matter and Materials Physics), [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=620541 (Accessed October 10, 2025)