SPICE Macromodel of Spin-Torque-Transfer-Operated Magnetic Tunnel Junctions

The electrical behavior of a magnetic tunnel junction (MTJ) using spin-torque-transfer (STT) switching was modeled using a SPICE subcircuit. The subcircuit is a two-terminal device that exhibits the electrical characteristics of an STT-MTJ. These characteristics include all the major transient characteristics of an MTJ, including the hysteresis, bias voltage dependence of the resistance, and the critical switching current versus the critical switching time. The model was designed to work over a wide range of operating conditions. Simulation and analysis of an MTJ-based D flip-flop are presented to demonstrate possible applications of the model.