Magnetoresistance anomaly during the electrical triggering of a metal-insulator transition

TL;DR

This study investigates how electrical triggering of a metal-insulator transition in ferromagnetic oxide (La,Sr)MnO3 induces phase separation, leading to magnetoresistance anomalies that can be electrically controlled, revealing new insights into magnetotransport behavior.

Contribution

It demonstrates that electrical switching can induce phase separation and magnetoresistance anomalies in LSMO, enabling electrical control of magnetotransport properties in such materials.

Findings

Magnetoresistance exhibits large magnitude increases and sign flips at the MIT threshold.

Phase separation forms an insulating barrier, affecting magnetotransport.

Anomalies originate from coupling between phase separation and intrinsic magnetoresistance.

Abstract

Phase separation naturally occurs in a variety of magnetic materials and it often has a major impact on both electric and magnetotransport properties. In resistive switching systems, phase separation can be created on demand by inducing local switching, which provides an opportunity to tune the electronic and magnetic state of the device by applying voltage. Here we explore the magnetotransport properties in the ferromagnetic oxide (La,Sr)MnO3 (LSMO) during the electrical triggering of an intrinsic metal-insulator transition (MIT) that produces volatile resistive switching. This switching occurs in a characteristic spatial pattern, i.e., the formation of an insulating barrier perpendicular to the current flow, enabling an electrically actuated ferromagnetic-paramagnetic-ferromagnetic phase separation. At the threshold voltage of the MIT triggering, both anisotropic and colossal magnetoresistances exhibit anomalies including a large increase in magnitude and a sign flip. Computational analysis revealed that these anomalies originate from the coupling between the switching-induced phase separation state and the intrinsic magnetoresistance of LSMO. This work demonstrates that driving the MIT material into an out-of-equilibrium resistive switching state provides the means to electrically control of the magnetotransport phenomena.