Switchable Exchange Bias Resulting from Correlated Domain Structures in Orthogonally Coupled Antiferromagnet/Ferromagnet van der Waals Heterostructures

TL;DR

This study demonstrates switchable exchange bias in vdW heterostructures due to interfacial exchange coupling, revealing how orthogonal magnetic anisotropies influence domain structures and magnetization reversal.

Contribution

It uncovers the microscopic mechanism of exchange bias in orthogonally coupled vdW heterostructures using magnetic imaging techniques.

Findings

Asymmetric magnetization reversal observed in FGT due to CrSBr coupling

Switchable exchange bias persists up to CrSBr's Néel temperature (132 K)

CrSBr influences domain configurations, promoting stripe-like structures in FGT

Abstract

Van der Waals (vdW) magnetic heterostructures offer a versatile platform for engineering interfacial spin interactions with atomic precision, enabling nontrivial spin textures and dynamic behaviors. In this work, we report robust asymmetric magnetization reversal and exchange bias in Fe3GeTe2 (FGT), driven by interlayer exchange coupling with the A-type antiferromagnet CrSBr. Despite the orthogonal magnetic anisotropies out-of-plane easy axis in FGT and in-plane in CrSBr, we observe a strong interfacial exchange interaction that gives rise to pronounced and switchable exchange bias and asymmetric switching in FGT, persisting up to the N\'eel temperature of CrSBr (132 K) as revealed by anomalous Hall effect measurements. We uncover the microscopic origin of this behavior through cross-sectional magnetic imaging of the domain structure using off-axis electron holography. The results reveal that the asymmetric switching and exchange bias arise from the influence of CrSBr on the domain configuration of FGT, where the in-plane antiferromagnetic state of CrSBr promotes the formation of stripe-like domain structures in FGT with circular rotation of magnetization in the cross-sectional bc plane defined by the easy axes of both FGT and CrSBr. These findings elucidate the mechanism of exchange bias in orthogonally coupled van der Waals systems and demonstrate a pathway for stabilizing three-dimensional domain structures in ferromagnets through interfacial exchange interactions.