Activation volumes in superparamagnetic Fe films determined using Brillouin Light scattering

Ultra-thin films of Fe grown in ultra-high-vacuum on GaAs (100) were studied using Brillouin light scattering. The films are not continuous but instead a collection of weakly interacting particles and are paramagnetic at room temperature. Spinwave frequency measurements can be used to determine anisotropies above the blocking temperature. In this paper, the authors show that temperature dependence can be used to provide a unique measure of particle volume.