Nature of field-induced transitions and hysteretic magnetoresistance in non-collinear antiferromagnet EuIn2As2

TL;DR

This study investigates the magnetic transitions and hysteretic magnetoresistance in EuIn2As2, revealing a field-induced transition and domain wall effects that influence electrical transport in a complex antiferromagnetic system.

Contribution

It provides experimental and theoretical insights into the magnetic states and transport phenomena in EuIn2As2, highlighting the role of domain walls and magnetic field effects.

Findings

Observation of a field-induced metamagnetic transition with hysteresis

Identification of a broken-helix antiferromagnetic state

Explanation of resistivity changes via domain wall dynamics

Abstract

We examine the magnetic and electrical transport properties of the hexagonal EuIn2As2 compound, combining experimental and theoretical results. This compound is predicted to be an axion-insulator from an electronic point of view and an altermagnet while in the collinear magnetic phase. However, experiments indicate that the Fermi level lies within the valence band rather than in the topological gap, potentially leading to the dominance of magnetic properties. Our detailed studies on magnetization and electrical transport support the presence of a broken-helix antiferromagnetic state, which was previously identified by X-ray and neutron diffraction experiments. Notably, we observed within that state a field-induced metamagnetic transition marked by a large hysteresis in magnetoresistance, which turns into a sharp upturn for the magnetic field tilted by 15 degree from the c-axis of the crystal. Combined with theoretical calculations, it is explained that the application of a magnetic field changes the low-resistivity antiferromagnetic domain walls to the high-resistivity domain walls due to the reduction in the Fermi surface sheets interaction area in the domain walls, originating from p-orbitals of As. EuIn2As2, therefore, presents a new case study that broadens the understanding of complex magnetic structures and their influence on electrical transport.