Domain wall motions in perpendicularly magnetized CoFe/Pd multilayer nanowire

TL;DR

This study investigates current-induced domain wall motion in a perpendicularly magnetized CoFe/Pd nanowire, revealing low current density requirements and the dominance of non-adiabatic spin transfer torque effects.

Contribution

It provides quantitative analysis of the roles of Oersted and spin transfer torque fields, highlighting the high non-adiabaticity in domain wall motion within multilayer nanowires.

Findings

Domain walls can be moved with current densities as low as 1.44×10^11 A/m^2.

Non-adiabatic spin transfer torque dominates the domain wall motion.

High non-adiabatic factor β up to 0.4 was observed.

Abstract

Current induced domain wall (DW) motion has been investigated in a 600-nm wide nanowire using multilayer film with a structure of Ta(5 nm)/Pd(5 nm)/[CoFe(0.4 nm)/Pd(1.2 nm)]$_{15}$/Ta(5 nm)in terms of anomalous Hall effect measurements. It is found that motion of DWs can be driven by a current density as low as 1.44$\times$10$^{11}$ A.m$^{-2}$. The effect of the Oersted field ($H_{Oe}$) and spin transfer torque field ($H_{ST}$), which are considered as effective fields for DW motion, has been quantitatively separated from the dependence of depinning fields on the current. The results show that the motion of the walls was essentially dominated by the non-adiabaticity with a high non-adiabatic factor $\beta$ up to 0.4.