Hydrodynamic theory of coupled current and magnetization dynamics in spin-textured antiferromagnets

TL;DR

This paper develops models for current-induced dynamics in antiferromagnetic textures, revealing how spin torques influence their motion and stability, with implications for spintronics applications.

Contribution

It introduces two models describing current-induced phenomena in antiferromagnetic textures, highlighting the roles of adiabatic and nonadiabatic spin torques and their effects on dynamics.

Findings

Adiabatic spin torque affects the lengthscale of antiferromagnetic textures.

Nonadiabatic spin torque can induce stable motion of textures.

Current can manipulate antiferromagnetic domain walls.

Abstract

Antiferromagnets with vanishingly small (or zero) magnetization are interesting candidates for spintronics applications. In the present paper we propose two models for description of the current-induced phenomena in antiferromagnetic textures. We show that the magnetization that originates from rotation or oscillations of antiferromagnetic vector can, via $sd$-exchange coupling, polarize the current and give rise to adiabatic and nonadiabatic spin torques. Due to the Lorentz-type dynamics of antiferromagnetic moments (unlike the Galilenian-like dynamics in ferromagnets), the adiabatic spin torque affects the characteristic lengthscale of the moving texture. Nonadiabatic spin torque contributes to the energy pumping and can induce the stable motion of antiferromagnetic texture, but, in contrast to ferromagnets, has pure dynamic origin. We also consider the current-induced phenomena in artificial antiferromagnets where the current maps the staggered magnetization of the structure. In this case the effect of nonadiabatic spin torque is similar to that in ferromagnetic constituents of the structure. In particular, the current can remove degeneracy of the translational antiferromagnetic domains indistinguishable in the external magnetic field and thus can set into motion the 180$^\circ$ domain wall.