Spin Angular Momentum Transfer in Magnetoresistive Nanojunctions

Abstract

High current density spin‐polarized transport in current‐perpendicular nanomagnetic junctions reveals an interaction between the spin‐polarized current and the nanomagnet electrodes. This interaction causes a current‐induced magnetic excitation in the ferromagnetic electrodes, leading either to persistent magnetic precession or to a complete magnetic reversal, under a dc current bias. This article gives a brief review of the basic understanding of this so‐called spin‐transfer phenomenon, including the basic mechanism, its early theoretical prediction and experimental discovery, and the significance of this interaction for applications in modern electronics. This review uses a framework of phenomenological analyses, bridging experimental observations and first‐principle‐based theoretical work.