Dependence of switching current distribution on current pulse width of current-induced magnetization switching in MgO-based magnetic tunnel junction

Current-induced magnetization switching in an MgO-based magnetic tunnel junction (MTJ) was experimentally studied. Probabilistic distribution of a switching current was measured at various current pulse widths from 5 μs to 100 ms. A thermal stability parameter Δ of a free-layer magnetic moment and an intrinsic switching current density J_c0 of the MTJ were evaluated from the switching current distribution using a thermal activation model. The estimated Δ and J_c0 were approximately independent of the pulse width and were in good agreement with the values estimated from the pulse-width dependence of the switching current density, demonstrating the validity of the thermal activation model.