Colossal magnetoresistance in Ti lightly-doped Cr2Se3 single crystals with layered structure

TL;DR

This study reports a colossal magnetoresistance effect exceeding 16000% in lightly Ti-doped Cr2Se3 single crystals, driven by frustrated spin configurations, with potential applications in spintronics.

Contribution

The paper demonstrates a significant enhancement of magnetoresistance in Ti-doped Cr2Se3, revealing new magnetic and electronic properties in layered antiferromagnets due to Ti doping.

Findings

CMR exceeds 16000% in Ti-doped Cr2Se3

Electronic conductivity changes from bad metal to semiconductor

Magnetic anisotropy shifts from out-of-plane to in-plane

Abstract

Stoichiometric Cr2Se3 single crystals are particular layer-structured antiferromagnets which possess noncolinear spin configuration, weak ferromagnetic moments, moderate magnetoresistance (MR ~ 14.3%), and bad metallic conductivity below the antiferromagnetic phase transition temperature. Here, we report an interesting >16000% colossal magnetoresistance (CMR) effect in Ti (1.5 atomic percent) lightly-doped Cr2Se3 single crystals. Such a CMR is approximately 1143 times larger than that of the stoichiometric Cr2Se3 crystals and is rarely observed in layered antiferromagnets and is attributed to the frustrated spin configuration. Moreover, the Ti doping not only dramatically changes the electronic conductivity of the Cr2Se3 crystal from a bad metal to a semiconductor with a gap of ~ 15 meV, but also induces a change of the magnetic anisotropy of the Cr2Se3 crystal from strong out-of-plane to weak in plane. Further, magnetotransport measurements reveal that the low-field MR scales with the square of the reduced magnetization, which is a signature of CMR materials. The layered Ti:Cr2Se3 with CMR effect could be used as 2D heterostructure building blocks to provide colossal negative MR in spintronic devices.