Exchange Bias and Interface-related Effects in Two-dimensional van der Waals Magnetic Heterostructures: Open Questions and Perspectives

TL;DR

This paper reviews the exchange bias effect in two-dimensional van der Waals magnetic heterostructures, discussing its physical origins, recent experimental findings, and future research directions for spintronic applications.

Contribution

It provides a comprehensive critical review of the exchange bias effect in vdW heterostructures and suggests approaches to address fundamental open questions.

Findings

Various vdW heterostructures exhibit intriguing exchange bias effects.

The physical origins of exchange bias in these systems remain largely elusive.

Proposed approaches aim to clarify the mechanisms behind exchange bias phenomena.

Abstract

The exchange bias (EB) effect is known as a fundamentally and technologically important magnetic property of a magnetic bilayer film. It is manifested as a horizontal shift in a magnetic hysteresis loop of a film subject to cooling in the presence of a magnetic field. The EB effect in van der Waals (vdW) heterostructures offers a novel approach for tuning the magnetic properties of the newly discovered single-layer magnets, as well as adds a new impetus to magnetic vdW heterostructures. Indeed, intriguing EB effects have recently been reported in a variety of low-dimensional vdW magnetic systems ranging from a weakly interlayer-coupled vdW magnet (e.g., Fe3GeTe2) to a bilayer composed of two different magnetic vdW materials (e.g., Fe3GeTe2/CrCl3, Fe3GeTe2/FePS3, Fe3GeTe2/MnPS3), to bilayers of two different vdW defective magnets (e.g., VSe2/MoS2), or to metallic ferromagnet/vdW defective magnet interfaces (e.g., Fe/MoS2). Despite their huge potential in spintronic device applications, the physical origins of the observed EB effects have remained elusive to researchers. We present here a critical review of the EB effect and associated phenomena such as magnetic proximity (MP) in various vdW heterostructure systems and propose approaches to addressing some of the emerging fundamental questions.