Linear and nonlinear spin dynamics in multi-domain magnetoelastic antiferromagnets

Abstract

Antiferromagnets have recently surged as the prominent material platform for the next generation spintronics devices. Despite the remarkable abundance of antiferromagnets and the variety of their spin textures in nature, they share a widely common, if not ubiquitous, feature. Magnetoelasticity, which is expressed as strictions of different origin, relativistic and/or exchange, significantly contributes to the magnetic anisotropy of antiferromagnets. Crucially, a general theoretical framework able to address the role of domain walls on the spin dynamics in antiferromagnets in the presence of magnetoelasticity is lacking. Here we tackle this problem developing a very general macroscopic phenomenological model. We demonstrate that the magnetoelasticity defines both the equilibrium and dynamical magnetic properties of easy-plane antiferromagnets in linear and nonlinear regimes. We employ our model to reproduce experimental results, showing that domain walls majorly affect the optically driven ultrafast nonlinear spin dynamics. Our model can be applied to a wide group of materials and, if properly extended, can be utilised to describe also other physical scenarios, key in the establishment of concepts for antiferromagnetic spintronics.