Reconfigurable Room Temperature Exchange Bias through N\'eel Order Switching in van der Waals Heterostructures

TL;DR

This study demonstrates the ability to reconfigure room temperature exchange bias in van der Waals heterostructures by switching Ne9el order, enabling advances in 2D spintronic devices.

Contribution

It introduces a method to control and switch exchange bias at room temperature via Ne9el order manipulation in van der Waals heterostructures with high magnetic ordering temperatures.

Findings

Achieved room temperature exchange bias in van der Waals heterostructures.

Controlled exchange bias sign and magnitude by manipulating Ne9el order.

Demonstrated switchable exchange bias through magnetic field-induced Ne9el order reversal.

Abstract

Exchange bias effect plays a crucial role in modern magnetic memory technology. Recently, van der Waals magnetic materials have emerged and shown potential in spintronic devices at atomic scale. Owing to their tunable physical properties and the flexibility in fabrication, the van der Waals heterostructures offer more possibilities for investigating potential mechanisms of the exchange bias effect. However, due to low magnetic ordering temperatures for most van der Waals magnets, to establish exchange bias in van der Waals antiferromagnet/ferromagnet heterostructures at room temperature is challenging. In this study, we fabricate (Fe$_{0.56}$Co$_{0.44}$)$_{5}$GeTe$_{2}$(FCGT)/Fe$_{3}$GaTe$_{2}$(FGaT) heterostructures with magnetic ordering temperatures of each component well above room temperature to achieve a room temperature exchange bias effect. It is found that the sign and magnitude of the exchange bias field can be efficiently controlled by manipulating the N\'eel order of FCGT with magnetic field. The manipulation of N\'eel order shows significant magnetic field dependence. A strong pre-set field induces a switch in the N\'eel order of FCGT, which aligns the interfacial magnetization at the FCGT/FGaT interface, leading to robust exchange bias, as revealed by both transport measurements and macro-spin model calculations. Our findings demonstrate the intrinsic manipulation and switchable of room-temperature exchange bias in all-van der Waals heterostructures and further promote the development of novel two-dimensional spintronic devices.