Current-Induced Dynamics in Almost Symmetric Magnetic Nanopillars

TL;DR

This paper investigates how spin transfer effects induce and influence magnetic precession in symmetric and asymmetric magnetic nanopillars, revealing role interchangeability and dynamic coupling between layers.

Contribution

It demonstrates the interchange of free and reference layer roles in nearly symmetric nanopillars and analyzes the dynamic coupling effects caused by spin transfer.

Findings

Precession can be induced in both layers in symmetric devices.

Asymmetry suppresses the dynamics of one layer.

Roles of layers interchange over a small thickness range.

Abstract

Magnetic nanodevices usually include a free layer whose configuration can be changed by spin-polarized current via the spin transfer effect, and a fixed reference layer. Here, we demonstrate that the roles of the free and the reference layers interchange over a small range of their relative thicknesses. Precession of both layers can be induced by spin transfer in symmetric devices, but the dynamics of one of the layers is rapidly suppressed in asymmetric devices. We interpret our results in terms of the dynamical coupling between magnetic layers due to spin transfer.