Current-induced domain-wall motion in synthetic antiferromagnets

TL;DR

This paper investigates how electric currents influence domain-wall motion in synthetic antiferromagnets, revealing a transition in noise behavior and suggesting spin transfer torques as the driving mechanism.

Contribution

It provides experimental evidence of current-induced domain-wall motion in synthetic antiferromagnets and links it to spin transfer torques, advancing understanding of magnetic dynamics under current.

Findings

Transition from excess to suppressed 1/f noise at j_c ~ 2*10^5 A/cm^2 in Fe/Cr multilayers

Domain wall noise remains unchanged up to 10^6 A/cm^2 in Co structures

Theoretical estimates support spin transfer torque as the mechanism

Abstract

Domain-wall magnetoresistance and low-frequency noise have been studied in epitaxial antiferromagnetically-coupled [Fe/Cr(001)]_10 multilayers and ferromagnetic Co line structures as a function of DC current intensity. In [Fe/Cr(001)]_10 multilayers a transition from excess to suppressed domain-wall induced 1/f noise above current densities of j_c ~ 2*10^5 A/cm^2 has been observed. In ferromagnetic Co line structures the domain wall related noise remains qualitatively unchanged up to current densities exceeding 10^6A/cm^2. Theoretical estimates of the critical current density for a synthetic Fe/Cr antiferromagnet suggest that this effect may be attributed to current-induced domain-wall motion that occurs via spin transfer torques.