Intriguing magnetoelectric effect in two-dimensional ferromagnetic/perovskite oxide ferroelectric heterostructure

Abstract Two-dimensional (2D) magnets have broad application prospects in the spintronics, but how to effectively control them with a small electric field is still an issue. Here we propose that 2D magnets can be efficiently controlled in a multiferroic heterostructure composed of 2D magnetic material and perovskite oxide ferroelectric (POF) whose dielectric polarization is easily flipped under a small electric field. We illustrate the feasibility of such strategy in the bilayer CrI 3 /BiFeO 3 (001) heterostructure by using the first-principles calculations. Different from the traditional POF multiferroic heterostructures which have strong interface interactions, we find that the interface interaction between CrI 3 and BiFeO 3 (001) is van der Waals type. Whereas, the heterostructure has particular strong magnetoelectric coupling where the bilayer CrI 3 can be efficiently switched between ferromagnetic and antiferromagnetic types by the polarized states P ↑ and P ↓ of BiFeO 3 (001). We also discover the competing effect between electron doping and the additional electric field on the interlayer exchange coupling interaction of CrI 3 , which is responsible to the magnetic phase transition. Our results provide a avenue for the tuning of 2D magnets with a small electric field.