Probing the spin dimensionality in single-layer CrSBr van der Waals heterostructures by magneto-transport measurements

TL;DR

This study investigates the magnetic and transport properties of single-layer CrSBr heterostructures, revealing low-dimensional ferromagnetic behavior, spin reorientation phenomena, and potential for 2D spintronic applications.

Contribution

It provides the first detailed magneto-transport analysis of CrSBr monolayers, demonstrating their complex magnetic behavior and suitability for 2D spintronic device integration.

Findings

CrSBr monolayers exhibit short-range magnetic correlations above Tc.

Spins align along the easy-axis b below Tc, showing Ising-type anisotropy.

Magnetoresistance is enhanced by magnetic field-induced spin reorientation.

Abstract

Two-dimensional (2D) magnetic materials offer unprecedented opportunities for fundamental physics and applied research in spintronics and magnonics. Beyond the pioneering studies on 2D CrI3 and Cr2Ge2Te6, this emerging field has expanded to 2D antiferromagnets exhibiting different spin anisotropies and textures. Of particular interest is the layered metamagnet CrSBr, a relatively air-stable semiconductor formed by antiferromagnetically-coupled ferromagnetic layers (Tc~150 K) that can be exfoliated down to the single-layer. It presents a complex magnetic behavior with a dynamic magnetic crossover leading to a low-temperature hidden order below T*~40 K. Here, we inspect the magneto-transport properties of CrSBr vertical heterostructures in the 2D limit. Our results demonstrate the marked low-dimensional character of the ferromagnetic monolayer, with short-range correlations above Tc and an Ising-type in-plane anisotropy, being the spins spontaneously aligned along the easy-axis b below Tc. By applying moderate magnetic fields along a and c axes, a spin reorientation occurs, leading to a magnetoresistance enhancement below T*. In multilayers, a spin-valve behavior is observed, with negative magnetoresistance strongly enhanced along the three directions below T*. These results show that CrSBr monolayer/bilayer provides an ideal platform for studying and controlling field-induced phenomena in two-dimensions, offering new insights regarding 2D magnets and their integration into vertical spintronic devices.