Electric-field control of the interlayer exchange coupling

Magnetization switching with electric-field is of great current interest to achieve high density and low energy non-volatile memory devices. We propose a new mechanism for electric-field controlled magnetization switching, assisted solely by the interlayer exchange coupling (IEC) between the fixed and the free magnets. Using non-equilibrium Green’s function (NEGF) method, we show that the resonant tunneling mechanism can tune the IEC with an electric-field, which in turn can switch the free magnet to have either a parallel or antiparallel configuration with respect to the fixed magnet, depending on the sign of the IEC. Such bi-directional switching can be achieved with the same voltage polarity but different magnitudes. Due to the 'conservative' nature of the exerted torque by IEC, the switching threshold is decoupled from the speed, while the conventional spin-torque devices exhibit a trade-off due to the 'non-conservative' nature of the exerted torque.