Yao Qi, Raja Das, et al.
ISSTA 2009
Spin angular momentum transfer, or spin-transfer, describes the transfer of spin angular momentum between a spin-polarized current and a ferromagnetic conductor. The angular momentum transfer exerts a torque (spin-current induced torque, or spin-torque) on the ferromagnetic conductor. When its dimensions are reduced to less than 100 nm, the spin-torque can become comparable to the magnetic damping torque at a spin-polarized current of high current density (above 106 A/cm2), giving rise to a new set of current-induced dynamic excitation and magnetic switching phenomena. This has now been definitively observed in sub-100-nm current-perpendicular spin-valves and magnetic tunnel junctions, and appears promising as a basis for direct write-address of a nanomagnetic bit when the lateral bit size is reduced to well below 100 nm. An overview is presented in this paper of spin-transfer phenomena. The first part of the paper contains a brief introduction to spin-transfer, especially the characteristic dynamics associated with spin-torque. In the second part, several representative experiments are described. In the third part, a set of basic phenomenological models are introduced that describe experimental observations. The models also serve as a bridge for quantitative comparison between experiments and first-principles spin-polarized transport theory. In the last part of the paper, some device concepts based on spin-transfer-induced magnetic excitation and magnetic reversal are described. ©Copyright 2006 by International Business Machines Corporation.
Yao Qi, Raja Das, et al.
ISSTA 2009
M.F. Cowlishaw
IBM Systems Journal
Yvonne Anne Pignolet, Stefan Schmid, et al.
Discrete Mathematics and Theoretical Computer Science
Thomas M. Cover
IEEE Trans. Inf. Theory