Optically-triggered strain-driven N\'{e}el vector manipulation in a metallic antiferromagnet

TL;DR

This paper demonstrates a method to control the Néel vector in a metallic antiferromagnet using combined strain and femtosecond laser pulses, enabling ultrafast, stable, and magnetic field-insensitive switching suitable for high-density memory applications.

Contribution

It introduces a novel optically-triggered, strain-assisted technique for manipulating the Néel vector in metallic antiferromagnets, advancing ultrafast spintronic device development.

Findings

Néel vector can be aligned via strain and femtosecond laser excitation.

The alignment results from depinning and sliding of domain walls.

The switchable state is stable at room temperature and insensitive to magnetic fields.

Abstract

The absence of stray fields, their insensitivity to external magnetic fields, and ultrafast dynamics make antiferromagnets promising candidates for active elements in spintronic devices. Here, we demonstrate manipulation of the N\'{e}el vector in the metallic collinear antiferromagnet Mn$_2$Au by combining strain and femtosecond laser excitation. Applying tensile strain along either of the two in-plane easy axes and locally exciting the sample by a train of femtosecond pulses, we align the N\'{e}el vector along the direction controlled by the applied strain. The dependence on the laser fluence and strain suggests the alignment is a result of optically-triggered depinning of 90$^{\mathrm{o}}$ domain walls and their sliding in the direction of the free energy gradient, governed by the magneto-elastic coupling. The resulting, switchable, state is stable at room temperature and insensitive to magnetic fields. Such an approach may provide ways to realize robust high-density memory device with switching timescales in the picosecond range.