Sign-tunable anisotropic magnetoresistance and electrically detectable dual magnetic phases in a helical antiferromagnet

TL;DR

This paper demonstrates a novel antiferromagnetic material EuCo2As2 exhibiting sign-reversible anisotropic magnetoresistance due to dual magnetic phases, highlighting its potential for advanced spintronic applications.

Contribution

It introduces EuCo2As2 as a new single-phase antiferromagnetic spintronic material with electrically detectable magnetic phase transitions and sign-reversible AMR.

Findings

Sign reversal of AMR in EuCo2As2 due to magnetic field-induced spin reorientation.

Identification of multiple AFM memory states linked to spin structure evolution.

Theoretical prediction of magnetic phases and their potential for spintronic device applications.

Abstract

The helimagnetic order describes a non-collinear spin texture of antiferromagnets, arising from competing exchange interactions. Although collinear antiferromagnets are elemental building blocks of antiferromagnetic (AFM) spintronics, the potential of implementing spintronic functionality in non-collinear antiferromagnets has not been clarified thus far. Here, we propose an AFM helimagnet of EuCo2As2 as a novel single-phase spintronic material that exhibits a remarkable sign reversal of anisotropic magnetoresistance (AMR). The contrast in the AMR arises from two electrically distinctive magnetic phases with spin reorientation driven by magnetic field lying on the easy-plane, which switches the sign of the AMR from positive to negative. Further, various AFM memory states associated with the evolution of the spin structure under magnetic fields were identified theoretically, based on an easy-plane anisotropic spin model. These results reveal that non-collinear antiferromagnets hold potential for developing spintronic devices.