Quantum Transport Simulation of Tunneling Based Spin Torque Transfer (STT) Devices: Design Trade offs and Torque Efficiency

We present a quantum transport simulation of tunneling based Spin Torque Transfer (STT) devices using the Non Equilibrium Green's Function (NEGF) formalism in the ballistic regime. We show that it is possible to achieve a quantitative agreement for both the tunneling magneto resistance (TMR) and the amplitude of the switching current with the same set of parameters. We also analyze the device performance as a function of parameter variations. Comparison with experiment shows that there is a lot of scope for improving the interface between the magnetic contact and the tunneling oxide, which, in turn, will improve the device performance significantly.