Non-Relativistic Anisotropic Magnetoresistance with Collinear and Non-Collinear Magnetic Order

TL;DR

This paper demonstrates that anisotropic magnetoresistance (AMR) can occur in non-relativistic systems purely due to magnetic order, without relying on spin-orbit coupling, expanding understanding of AMR mechanisms.

Contribution

It reveals that magnetic order alone can induce significant AMR in non-relativistic systems, supported by theoretical models and real material case studies.

Findings

AMR can emerge without spin-orbit coupling

Magnetic order induces symmetry lowering in conductivity

Material candidates identified for non-relativistic AMR

Abstract

Anisotropic magnetoresistance (AMR) arises from symmetry lowering of the conductivity tensor induced by magnetic order. In simple ferromagnets, AMR is a relativistic effect, relying on spin-orbit interaction (SOC). Here, we demonstrate that a comparable symmetry lowering can also occur in a non-relativistic limit. Using tight-binding models, density functional theory calculations, and Boltzmann transport theory, we investigate systems with multiple magnetic sublattices, including both collinear and non-collinear antiferromagnets, as well as ferrimagnetic configurations. We show that AMR and related anisotropies can emerge purely from magnetic order, without the need for SOC, and may reach significant magnitudes. The findings are supported by case studies on toy-model lattices and real materials such as MnN, Mn$_3$Sn, and are further interpreted using a symmetry analysis based on Neumann's principle. Material candidates that exhibit non-relativistic anisotropic magnetoresistance are identified by symmetry analysis applied to entries in the MAGNDATA database.