Current-driven excitations in magnetic multilayers: a brief review

TL;DR

This review discusses the experimental observations and models of current-driven magnetic excitations and switching in multilayer structures, highlighting their potential applications in memory devices and microwave sources.

Contribution

It summarizes recent experimental findings and theoretical models related to current-induced magnetic phenomena in multilayers, emphasizing technological implications.

Findings

Observation of current-driven magnetization switching

Detection of spin-wave excitations induced by current

Potential applications in MRAM and microwave generation

Abstract

In 1996, Berger and Slonczewski independently predicted that a large enough spin-polarized dc current density sent perpendicularly through a ferromagnetic layer could produce magnetic excitations (spin-waves) or reversal of magnetization (switching). In the past few years, both current-driven switching and current-driven excitation of spin-waves have been observed. The switching is of potential technological interest for direct 'writing' of magnetic random access memory (MRAM) or magnetic media. The spin-wave generation could provide a new source of dc generated microwave radiation. We describe what has been learned experimentally about these two related phenomena, and some models being tested to explain these observations.