Identification of N\'eel vector orientation in antiferromagnetic domains switched by currents in NiO/Pt thin films

TL;DR

This study identifies and quantifies the Néel vector orientation changes in NiO/Pt antiferromagnetic thin films caused by electrical currents, providing insights crucial for designing high-frequency antiferromagnetic spintronic devices.

Contribution

It reveals the crystallographic domain orientations switchable by currents and quantifies the magnetoelastic coupling in NiO thin films, advancing understanding of current-induced antiferromagnetic switching.

Findings

Néel vector orientation in domains is along [±5 ±5 19], different from bulk directions.

Electrical switching aligns Néel vector with current direction.

Magnetoelastic coupling coefficient estimated as 3×10^7 J/m^3.

Abstract

Understanding the electrical manipulation of antiferromagnetic order is a crucial aspect to enable the design of antiferromagnetic devices working at THz frequency. Focusing on collinear insulating antiferromagnetic NiO/Pt thin films as a materials platform, we identify the crystallographic orientation of the domains that can be switched by currents and quantify the N\'eel vector direction changes. We demonstrate electrical switching between different T-domains by current pulses, finding that the N\'eel vector orientation in these domains is along $[\pm5\ \pm5\ 19]$, different compared to the bulk $<11\bar{2}>$ directions. The final state of the N\'eel vector $\textbf{n}$ switching after current pulses $\textbf{j}$ along the $[1\ \pm1\ 0]$ directions is $\textbf{n}\parallel \textbf{j}$. By comparing the observed N\'eel vector orientation and the strain in the thin films, assuming that this variation arises solely from magnetoelastic effects, we quantify the order of magnitude of the magnetoelastic coupling coefficient as $b_{0}+2b_{1}=3*10^7 J\ m^{-3}$ . This information is key for the understanding of current-induced switching in antiferromagnets and for the design and use of such devices as active elements in spintronic devices.