Configurable antiferromagnetic domains and lateral exchange bias in atomically thin CrPS4

TL;DR

This study demonstrates how interfacial control in atomically thin CrPS4 enables tunable antiferromagnetic domains and exchange bias, advancing the understanding of 2D AFM-FM hybrid systems.

Contribution

It reveals a method to control antiferromagnetic domains and exchange bias in 2D CrPS4 via intralayer exchange coupling and surface magnetization.

Findings

Lateral control of AFM domains achieved in CrPS4

Tunable multilevel exchange bias demonstrated

Nanoscale visualization of exchange bias origins

Abstract

Interfacial exchange coupling between antiferromagnets (AFMs) and ferromagnets (FMs) crucially makes it possible to shift the FM hysteresis, known as exchange bias, and to switch AFM states. Two-dimensional magnets unlock opportunities to combine AFM and FM materials; however, the buried AFM-FM interfaces obtained by stacking remains challenging to understand. Here we demonstrate interfacial control via intralayer exchange coupling in the layered AFM CrPS$_4$, where connected even and odd layers realize pristine lateral interfaces between AFM-like and FM-like regions. We distinguish antiphase even-layer states by scanning nitrogen-vacancy centre (NV) magnetometry due to a weak surface magnetization. This surface magnetization enables control over the even-layer state, with different regions switching at distinct fields due to their own lateral couplings. We toggle three AFM domains adjacent to a FM-like region and demonstrate a tunable multilevel exchange bias. Our nanoscale visualization unveils the microscopic origins of exchange bias and advances single two-dimensional crystals for hybrid AFM-FM technologies.