Magnetoresistance driven by the magnetic Berezinskii-Kosterlitz-Thouless transition

TL;DR

This paper explores how the Berezinskii-Kosterlitz-Thouless transition influences magnetoresistance in magnetic systems, revealing a defect density-dependent effect that intensifies above the transition temperature.

Contribution

It provides a theoretical framework linking topological magnetic defects to magnetoresistance near the BKT transition in ferromagnetic metals.

Findings

Magnetoresistance scales with defect density.

Electron scattering on magnetic textures affects resistance.

Magnetoresistance increases above the BKT transition temperature.

Abstract

While the Berezinskii-Kosterlitz-Thouless transition (BKT) has been under intense scrutiny for decades, unambiguous experimental signatures in magnetic systems remain elusive. Here, we investigate the interplay between electronic and magnetic degrees of freedom near the BKT transition. Focusing on a metal with easy-plane ferromagnetic order, we establish a framework that accounts both for the coupling between the charge current and the flow of topological magnetic defects and for electron scattering on their inhomogeneous spin texture. We show that electron scattering is responsible for a temperature-dependent magnetoresistance effect scaling as the density of the topological defects, which is expected to increase dramatically above the BKT transition temperature. Our findings call for further experimental investigations.