Current-driven Magnetization Reversal and Spin Wave Excitations in Co/Cu/Co Pillars

TL;DR

This paper investigates how spin-polarized currents can switch magnetization states and excite spin waves in Co/Cu/Co nanopillars, demonstrating the effects of spin-transfer torques in nanoscale magnetic devices.

Contribution

It provides experimental evidence of current-induced magnetization reversal and spin wave excitations in Co/Cu/Co pillars, confirming spin-transfer theory predictions.

Findings

Current flow can switch magnetic states between parallel and antiparallel.

High magnetic fields induce spin-wave excitations instead of full reversal.

The results support the role of spin-transfer torques in nanoscale magnetic control.

Abstract

Using thin film pillars ~100 nm in diameter, containing two ferromagnetic Co layers of different thicknesses separated by a paramagnetic Cu spacer, we examine effects of torques due to spin-polarized currents flowing perpendicular to the layers. In accordance with spin-transfer theory, spin-polarized electrons flowing from the thin to the thick Co layer can switch the magnetic moments of the layers antiparallel, while a reversed electron flow causes switching to a parallel state. When large magnetic fields are applied, the current no longer fully reverses the magnetic moment, but instead stimulates spin-wave excitations.