Electric field control of magnetism is an important approach to developing low-power spintronic devices and has become a significant research direction in magnetism. Recently, multiferroics have attracted much attention due to their ability to control magnetism via magnetoelectric coupling by using electric fields. Especially in ferromagnetic/ferroelectric multiferroic heterostructures, remarkable electric-field modulation of magnetism has been realized at room temperature. In this paper, we give an overview of recent progress of electric-field control of magnetism and magnetic tunnel junctions in multiferroic heterostructures. This review consists of five parts: 1) introduction of magnetic tunnel junctions (MTJs) and the related control technologies; 2) multiferroics and the mechanism of electric-field-controlled magnetism in multiferroic heterostructures; 3) electric-field control of in-plane MTJs; 4) electric-field control of perpendicular magnetization and perpendicular MTJs; 5) the perspective of multiferroic heterostructures.

The first part introduces the basic concepts of MTJs and the method of controlling an MTJ by adjusting the magnetization of the free layer. The second part briefly reviews multiferroics and magnetoelectric coupling. To achieve significant electric-field control over magnetism, different mechanisms of magnetoelectric coupling in multiferroic heterostructures are discussed, i.e. charge-mediated, strain-mediated, and exchange-mediated.

For magnetic film with in-plane magnetic anisotropy, electric field can effectively rotate its magnetization via strain-mediated magnetoelectric coupling. Therefore, the resistance of an MTJ is manipulated by electric fields due to the 90° magnetization rotation of the free layer. Furthermore, full electrical switching of the MTJ is achieved through introducing multiple strain and using dipole interaction.

Perpendicular magnetic anisotropy is essential for magnetic storage to increase the storage density and thermal stability, therefore, great efforts have been dedicated to manipulating perpendicular magnetization by electric fields. In multiferroic heterostructures, strain-mediated electrically control of perpendicular magnetization is introduced. Moreover, switching perpendicular magnetization is realized in ferrimagnetic/ferroelectric multiferroic heterostructures through modulating the compensation temperature. Then electric-field control of perpendicular MTJs is reported. Finally, a perspective of multiferroic heterostructures is given.