  The realistic modeling of STT-MRAM for the simulations of hybrid
CMOS/Spintronics devices in comprehensive simulation environments require a
full description of stochastic switching processes in state of the art
STT-MRAM. Here, we derive an analytical formulation that takes into account the
spin-torque asymmetry of the spin polarization function of magnetic tunnel
junctions studying. We studied its validity range by comparing the analytical
formulas with results achieved numerically within a full micromagnetic
framework. We also find that a reasonable fit of the probability density
function (PDF) of the switching time is given by a Pearson Type IV PDF. The
main results of this work underlines the need of data-driven design of STT-MRAM
that uses a full micromagnetic simulation framework for the statistical
proprieties PDF of switching processes.
