Observation of an Unusual Colossal Anisotropic Magnetoresistance Effect in an Antiferromagnetic Semiconductor

TL;DR

This paper reports a colossal anisotropic magnetoresistance effect in EuTe2, an antiferromagnetic semiconductor, driven by a novel band structure mechanism, opening new avenues for antiferromagnetic spintronics.

Contribution

It introduces a new mechanism for colossal AMR in an antiferromagnetic material, distinct from conventional spin-orbit coupling, based on vector-field tunable band structure and orbital hybridization.

Findings

AMR reaches 40000%, four orders of magnitude larger than in conventional AFM alloys

The colossal AMR is due to a vector-field tunable band structure, not spin-orbit coupling

Strong hybridization between Eu-layer and Te-layer orbitals is crucial

Abstract

Searching for novel antiferromagnetic materials with large magnetotransport response is highly demanded for constructing future spintronic devices with high stability, fast switching speed, and high density. Here we report a colossal anisotropic magnetoresistance effect in an antiferromagnetic binary compound with layered structure rare-earth dichalcogenide EuTe2. The AMR reaches 40000%, which is 4 orders of magnitude larger than that in conventional antiferromagnetic alloys. Combined magnetization, resistivity, and theoretical analysis reveal that the colossal AMR effect is attributed to a novel mechanism of vector-field tunable band structure, rather than the conventional spin-orbit coupling mechanism. Moreover, it is revealed that the strong hybridization between orbitals of Eu-layer with localized spin and Te-layer with itinerant carriers is extremely important for the large AMR effect. Our results suggest a new direction towards exploring AFM materials with prominent magnetotransport properties, which creates an unprecedented opportunity for AFM spintronics applications.