Oersted field and spin current effects on magnetic domains in [Co/Pd]15 nanowires

TL;DR

This study investigates how Oersted fields and spin currents influence magnetic domain formation in [Co/Pd]15 nanowires, revealing that current-induced heating promotes domain growth despite low spin transfer efficiency.

Contribution

It demonstrates the effects of localized Oersted fields and Joule heating on domain formation and growth in Co/Pd nanowires, combining experimental and modeling approaches.

Findings

Oersted field induces local domain reversal in nanowires.

Joule heating promotes domain growth below coercive field.

Low spin transfer efficiency prevents domain wall motion at high current densities.

Abstract

An out-of-plane Oersted field produced from a current-carrying Au wire is used to induce local domain formation in wires made from [Co/Pd]15 multilayers with perpendicular anisotropy. A 100 ns pulsed current of 56-110 mA injected into the Au wire created a reverse domain size of 120-290 nm in a Co/Pd nanowire on one side of the Au wire. A Biot-Savart model was used to estimate the position dependence of the Oersted field around the Au wire. The shape, size and location of the reversed region of Co/Pd was consistent with the magnitude of the Oersted field and the switching field distribution of the unpatterned film. A current density of 6.2 x 10^11 A m-2 in the Co/Pd nanowire did not translate the domain walls due to low spin transfer efficiency, but the Joule heating promoted domain growth in a field below the coercive field.