Growth and Kerr magnetometry of Mn2Au on a gold-capped Nb(001) substrate

TL;DR

This study investigates the epitaxial growth of Mn2Au on Nb(001), its interface properties, and how these influence magnetic coupling with Fe layers, providing insights relevant for spintronic device development.

Contribution

It demonstrates controlled growth of Mn2Au on Nb(001), analyzes interface effects on magnetic coupling, and highlights the importance of interface termination for spintronic applications.

Findings

Layer-by-layer growth confirmed by electron diffraction.

Exchange bias can be set by field-cooling from 400 K.

Postannealing reduces magnetic coupling areas.

Abstract

We report on the epitaxial growth of antiferromagnetic Mn2Au on a Nb(001) substrate capped with a pseudomorphic layer of gold. We observe a layer-by-layer growth by means of medium-energy electron diffraction and confirm stoichiometry and surface structure by Auger electron spectroscopy and low-energy electron diffraction. Evaporation of 15 ML of ferromagnetic Fe on 12--17 ML of Mn2Au results in an exchange-coupled bilayer system with an exchange-bias shift that can be set by field-cooling from 400 K. Areas with and without exchange bias, with domain sizes in the range of tens of {\mu}m, are identified by Kerr microscopy. Postannealing the sample at or above 450 K after Mn2Au layer growth decreases the amount of areas where Fe magnetically couples to Mn2Au. We conclude that exchange coupling to an interfacial Fe layer depends on the interface termination of Mn2Au. Our findings provide insight into the growth process of Mn2Au and the coupling to an Fe layer. Our results point out the importance of growth, interface quality and termination on the magnetic properties of a Mn2Au/Fe bilayer which may help to improve material properties for spintronic applications.