Voltage-controlled magnetic anisotropy in heterostructures with a two-dimensional magnetic material

Abstract

The advent of two-dimensional (2D) magnetic materials significantly expand the scope of voltage-controlled magnetization-switching scheme as their integration in diverse magnetic tunnel junctions (MTJ) offers a highly attractive perspective for designing future magnetoelectric random access memory (MeRAM). Here, we propose the utilization of 2D ferromagnetic Fe2I2 to substitute traditional magnetic thin films for assembling energy-efficient MTJs combined with Ir capping layers. We find these multilayers exhibit both giant perpendicular magnetic anisotropy (PMA) and voltage controlled magnetic anisotropy (VCMA) efficiency depending strongly on the Ir thickness and epitaxial strain effect. Furthermore, the spin reorientation has also been achieved with increased Ir thickness, and the magnitude and slope of VCMA behavior are dominated by the biaxial strain. We elucidate that the underlying mechanism is the electric-field-induced modifications of the spin-orbit coupling energies of the spin-polarized Ir-d orbitals. These findings not only reveal new approaches controlling 2D magnetism, but also pave the way of an alternative strategy for the design of nonvolatile and ultralow power spintronics and magnetic memory storage devices.