Electric-field switching of two-dimensional van der Waals magnets

TL;DR

This paper demonstrates the electrical control of magnetism in bilayer CrI3, a 2D van der Waals antiferromagnetic semiconductor, using small gate voltages to switch between magnetic states via a large linear magnetoelectric effect.

Contribution

It shows reversible electrical switching of magnetic states in bilayer CrI3 through electric-field-induced interlayer exchange bias, a novel control method for 2D magnetic materials.

Findings

Electric field induces a large linear magnetoelectric effect.

Reversible switching between AFM and FM states achieved.

Magnetization detected by magnetic circular dichroism microscopy.

Abstract

Controlling magnetism by purely electrical means is a key challenge to better information technology1. A variety of material systems, including ferromagnetic (FM) metals2,3,4, FM semiconductors5, multiferroics6,7,8 and magnetoelectric (ME) materials9,10, have been explored for the electric-field control of magnetism. The recent discovery of two-dimensional (2D) van der Waals magnets11,12 has opened a new door for the electrical control of magnetism at the nanometre scale through a van der Waals heterostructure device platform13. Here we demonstrate the control of magnetism in bilayer CrI3, an antiferromagnetic (AFM) semiconductor in its ground state12, by the application of small gate voltages in field-effect devices and the detection of magnetization using magnetic circular dichroism (MCD) microscopy. The applied electric field creates an interlayer potential difference, which results in a large linear ME effect, whose sign depends on the interlayer AFM order. We also achieve a complete and reversible electrical switching between the interlayer AFM and FM states in the vicinity of the interlayer spin-flip transition. The effect originates from the electric-field dependence of the interlayer exchange bias.