Magnetoresistance effects in the metallic antiferromagnet Mn$_2$Au

TL;DR

This study investigates magnetoresistance effects in epitaxial Mn2Au thin films, revealing anisotropic magnetoresistance and domain wall annihilation effects induced by high magnetic field pulses, relevant for antiferromagnetic spintronics.

Contribution

It provides the first detailed measurement of magnetoresistance effects in Mn2Au under high magnetic fields, highlighting anisotropic responses and domain wall dynamics.

Findings

Anisotropic magnetoresistance of -0.15% along the easy [110] direction.

Larger anisotropic magnetoresistance observed along the hard [100] direction.

Transient 1% resistance reduction linked to antiferromagnetic domain wall annihilation.

Abstract

In antiferromagnetic spintronics, it is essential to separate the resistance modifications of purely magnetic origin from other effects generated by current pulses intended to switch the N\'eel vector. We investigate the magnetoresistance effects resulting from magnetic field induced reorientations of the staggered magnetization of epitaxial antiferromagnetic Mn2Au(001) thin films. The samples were exposed to 60 T magnetic field pulses along different crystallographic in-plane directions of Mn2Au(001), while their resistance was measured. For the staggered magnetization aligned via a spin-flop transition parallel to the easy [110]-direction, an ansiotropic magnetoresistance of -0.15 % was measured. In the case of a forced alignment of the staggered magnetization parallel to the hard [100]-direction, evidence for a larger anisotropic magnetoresistance effect was found. Furthermore, transient resistance reductions of about 1 % were observed, which we associate with the annihilation of antiferromagnetic domain walls by the magnetic field pulses.