Perpendicular magnetic anisotropy and its electric-field-induced change at metal-dielectric interfaces

Electric-field-induced control of magnetic properties at room temperature has attracted considerable attention owing to its significant potential for facilitating the construction of ultralow-power-consumption electric devices. Voltage-controlled magnetic anisotropy (VCMA) effect in ultrathin ferromagnetic metals has shown that the magnetization of nanomagnets can be controlled by electric fields in extremely short periods (down to 0.1 ns). The VCMA effect in metals can be the ultimate technology for the operation of spintronics devices, such as nonvolatile random access memory, where high-speed operation with high writing endurance is indispensable. This review summarizes experimental studies of the VCMA effect. First, studies on VCMA in various systems are reviewed. Then, useful experimental and theoretical methods for VCMA research, i.e. electrical measurements using magnetic tunnel junction devices, x-ray magnetic circular dichroism spectroscopy, and first-principles studies, are described. Finally, the oxygen ion migration mechanism for electrochemical VCMA and the orbital magnetic moment and electric quadrupole mechanisms for purely electronic VCMA are discussed in detail.