Monte-Carlo Simulations of Magnetic Tunnel Junctions: From physics to application

Magnetic Tunnel Junctions (MTJs) - the basic structures of the Spin-Transfer Torque Magnetic RAMs (STT-MRAM) currently reaching the market - present a complex and probabilistic switching behavior. Although some analytical models describing this behavior exist, they can not describe all the switching regimes of the MTJs. They can model low (“subcritical”) and high (“supercritical”) currents, but not the intermediate currents, which are essential for applications. In this work, we present Monte-Carlo simulations of MTJs that have been used to build an analytical model linking the two different current regimes. This model allowed us to perform system-level simulations of an original neuro-inspired chip that uses MTJs as binary stochastic “synapses”.