Voltage-induced switching in magnetic tunnel junctions with perpendicular magnetic anisotropy

Spintronic devices can be operated by either a magnetic field or a spin polarized current; however, the former is not site-specific, and the latter suffers from large current density issues. In this work, we show that voltage-controlled spintronic devices offer many attributes. Although a metallic ferromagnet responds only very weakly to an electric field if at all, under special circumstances an electric field can have a profound impact on its magnetic properties. An electric field can alter the interfacial perpendicular magnetic anisotropy (PMA) of CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) in a prescribed manner. By exploiting the voltage dependence of the PMA we have accomplished voltage-controlled MTJ for which the high- and low-resistance states can be accessed reversibly and repeatedly by voltage pulses associated with very low current density in the range of 10⁴ A cm^-2. This development opens up a new avenue to achieve ultra-low power consumption and ultra-fast operation in next-generation spintronic devices.