Importance Sampling for Thermally Induced Switching and Non-Switching Probabilities in Spin-Torque Magnetic Nanodevices

Abstract

Spin-transfer torque magnetoresistive random access memory is a potentially transformative technology in the non-volatile memory market. Its viability depends, in part, on one's ability to predictably induce or prevent switching; however, thermal fluctuations cause small but important errors in both the writing and reading processes. Computing these very small probabilities for magnetic nanodevices using naive Monte Carlo simulations is essentially impossible due to their slow statistical convergence, but variance reduction techniques can offer an effective way to improve their efficiency. Here, we provide an illustration of how importance sampling can be efficiently used to estimate low read and write soft error rates of macrospin and coupled-spin systems.

Switching time of spin-torque-driven magnetization in biaxial ferromagnets

“…The dynamics of magnetization subject to an effective magnetic field, intrinsic damping, and spin torque is described by the Landau-Lifshitz-Gilbert (LLG) equation. Using dimensionless form of physical parameters listed in Table I, the LLG equation is 24,27…”