Epitaxial growth, structural characterization and exchange bias of non-collinear antiferromagnetic Mn$_{3}$Ir thin films

TL;DR

This study explores the epitaxial growth, structural properties, and exchange bias effects in non-collinear antiferromagnetic Mn₃Ir thin films, highlighting their potential for spintronic applications.

Contribution

It demonstrates controlled epitaxial growth of Mn₃Ir films with specific orientations and investigates their magnetic exchange bias properties at room temperature.

Findings

Exchange bias fields up to -29 mT at room temperature.

Dependence of blocking temperature on crystallographic direction.

High-quality epitaxial Mn₃Ir films achieved on MgO and Al₂O₃ substrates.

Abstract

Antiferromagnetic materials are of great interest for spintronics. Here we present a comprehensive study of the growth, structural characterization, and resulting magnetic properties of thin films of the non-collinear antiferromagnet Mn$_{3}$Ir. Using epitaxial engineering on MgO (001) and Al$_{2}$O$_{3}$ (0001) single crystal substrates, we control the growth of cubic ${\gamma}$-Mn$_{3}$Ir in both (001) and (111) crystal orientations, and discuss the optimization of growth conditions to achieve high-quality crystal structures with low surface roughness. Exchange bias is studied in bilayers, with exchange bias fields as large as -29 mT (equivalent to a unidirectional anisotropy constant of 11.5 nJ cm$^{-2}$) measured in Mn$_{3}$Ir (111) / permalloy heterostructures at room temperature. In addition, a distinct dependence of blocking temperature on in-plane crystallographic direction in Mn$_{3}$Ir (001) / Py bilayers is observed. These findings are discussed in the context of chiral antiferromagnetic domain structures, and will inform progress towards topological antiferromagnetic spintronic devices.