Thermal magnetoresistance from magnon scattering from a domain wall in an antiferromagnetic insulator

TL;DR

This paper theoretically explores how a magnetic field influences magnon heat transport across a domain wall in an antiferromagnetic insulator, revealing a mechanism for thermal magnetoresistance that can be used to control magnonic heat currents.

Contribution

It introduces a theoretical model showing how magnetic fields affect magnon transmission through domain walls, leading to controllable thermal magnetoresistance in antiferromagnetic insulators.

Findings

Magnetic field modifies magnon mode degeneracy and occupation.

Finite reflection at the domain wall impacts heat transport.

Magnetic field enables control of magnon heat current.

Abstract

We theoretically investigate magnon heat transport in an antiferromagnetic (AFM) insulator containing a domain wall (DW) in the presence of a magnetic field applied along the easy axis. We show that the intrinsic spin of the DW couples to the external magnetic field which modifies the transmission of spin wave (SW) through the DW. Applying the magnetic field lifts the degeneracy between two AFM magnon modes and results in different occupation numbers for the two magnon modes. Combined with the finite reflection of a narrow domain wall, this is found to have a significant impact on the magnon heat transport, giving rise to thermal magnetoresistance. Our findings suggest that an AFM DW can be used as a controllable element for regulating the magnon heat current in magnonic devices through the application of a magnetic field.