Thermally activated magnetization reversal in submicron magnetic tunnel junctions for magnetoresistive random access memory

We have measured thermally activated magnetization reversal of the free layers in submicron magnetic tunnel junctions to be used for magnetoresistive random access memory. We applied magnetic field pulses to the bits with a pulse duration $t_p$ ranging from nanoseconds to 0.1 ms. We have measured the switching probability as a function of $t_p$ with a fixed field amplitude $\mathrm{H,}$ and as a function of $H$ for fixed $t_p.$ For both cases, we find good agreement with the switching probability predicted by the Arrhenius–Néel theory for thermal activation over a single energy barrier.