Nonvolatile magnetoelectric coupling in two-dimensional ferromagnetic-bilayer/ferroelectric van der Waals heterostructures

Abstract

One of the promising research topics on two-dimensional (2D) van der Waals (vdW) material based devices is the nonvolatile electrical control of magnetism. Usually, it is very hard to tune ferromagnetic or antiferromagnetic ordering by ferroelectric polarization due to strong exchange coupling. The existence of vdW layer spacing, however, which is ubiquitous in 2D materials, makes interlayer magnetic exchange coupling much weaker than interlayer coupling. In this work, we design a multiferroic heterostructure composed of a CrOBr ferromagnetic bilayer and an In₂Se₃ ferroelectric monolayer. The weaker interlayer exchange coupling of the CrOBr bilayer makes it easier to be regulated by ferroelectric polarization, enabling reversible nonvolatile electric control of shifts between ferromagnetic and antiferromagnetic ordering. The unique electrically controlled interlayer magnetic coupling for tuning the overall magnetism may be available for the practical application of 2D vdW bilayer magnets in high-sensitivity sensors and high-density data storage.