Controlling the 2D magnetism of CrBr$_3$ by van der Waals stacking engineering

TL;DR

This paper demonstrates the control of 2D magnetism in CrBr3 by manipulating interlayer stacking through strain engineering, revealing the correlation between stacking order and magnetic phases, with potential applications in spintronics.

Contribution

It introduces a method to control interlayer stacking and magnetic states in CrBr3 using thermally assisted strain, confirmed by advanced imaging and first-principles calculations.

Findings

Realization of stable FM, AFM, and coexistent magnetic states.

Correlation between stacking order and magnetic phase.

Observation of tunable exchange bias effect.

Abstract

The manipulation of two-dimensional (2D) magnetic order is of significant importance to facilitate future 2D magnets for low-power and high-speed spintronic devices. Van der Waals stacking engineering makes promises for controllable magnetism via interlayer magnetic coupling. However, directly examining the stacking order changes accompanying magnetic order transitions at the atomic scale and preparing device-ready 2D magnets with controllable magnetic orders remain elusive. Here, we demonstrate effective control of interlayer stacking in exfoliated CrBr$_3$ via thermally assisted strain engineering. The stable interlayer ferromagnetic (FM), antiferromagnetic (AFM), and FM-AFM coexistent ground states confirmed by the magnetic circular dichroism measurements are realized. Combined with the first-principles calculations, the atomically-resolved imaging technique reveals the correlation between magnetic order and interlay stacking order in the CrBr$_3$ flakes unambiguously. A tunable exchange bias effect is obtained in the mixed phase of FM and AFM states. This work will introduce new magnetic properties by controlling the stacking order, and sequence of 2D magnets, providing ample opportunities for their application in spintronic devices.