Thermal activation-induced sweep-rate dependence of magnetic switching astroid

We examine the sweep-rate dependence of magnetic switching field, $H_s,$ in submicron magnetic tunnel junctions where shape anisotropy is dominant. Experimental data support the use of a single-domain thermal activation model for description of activated magnetic reversal in junctions 0.2 by 0.5 μm or less in size. A scaling law is obtained for the thermal activation energy which varies as the cube of junction size.