Micromagnetic analysis of statistical switching in perpendicular STT-MRAM with interfacial Dzyaloshinskii–Moriya Interaction

The technological implementation of STT-MRAMs in real devices needs a complete description of the statistical switching behavior at room temperature. In this work, we investigate, by means of a full micromagnetic model, the effect of the interfacial Dzyaloshinskii–Moriya Interaction (IDMI) on the critical current density and probability density function (PDF) of the switching time in perpendicular STT-MRAMs. We show that, for large enough values of the symmetric exchange interaction, the negative effect of the IDMI on the critical current is strongly reduced. In addition, a comprehensive analysis of the four main statistical moments (mean, standard deviation, skewness and kurtosis) points out that to fit the switching time PDF in order to maintain a quadratic error at least one order of magnitude smaller than Skew Normal PDF, a Pearson Type IV PDF has to be used also in presence of the IDMI.