Magnetic field control of antiferromagnetic domain walls in a thermal gradient

TL;DR

This paper demonstrates how a uniform magnetic field can control antiferromagnetic domain wall movement in a thermal gradient by inducing a force that overcomes entropic effects, enabling precise domain wall manipulation.

Contribution

It introduces a method to control antiferromagnetic domain walls using magnetic fields in thermal gradients, revealing a new mechanism based on magnon reflection and domain wall reflectivity.

Findings

Magnetic field induces a force on domain walls towards colder regions.

Force magnitude increases with magnetic field strength and thermal gradient.

Reflectivity of domain walls to magnons is key to controlling their motion.

Abstract

An antiferromagnetic domain wall in a thermal gradient is found to experience a force towards colder regions upon the application of a uniform magnetic field along the easy axis. This force increases with the strength of the applied field and, for sufficiently high values, it overcomes the entropic force the that pushes wall towards the hotter regions. The force is proportional to the thermal gradient and it shows a linear dependence with the net magnetic moment of the domain wall induced by the field. The origin of this force lies on the increase of the domain wall reflectivity due the field-induced sizable break of antiferromagnetic order inside it, which turns it into an efficient barrier for magnons, which transfer linear momentum to the domain wall when they are reflected on it