Analysis of magnetic aftereffects in nanocrystalline SmFeCo by the Preisach hysteresis model

Magnetic viscosity measurements performed on nanocrystalline SmFeCo spring magnets with different Fe content are analyzed by the Preisach hysteresis model. The model gives a unified description of hysteresis and relaxation properties. Comparison between calculated and measured viscosity permits one to estimate the aftereffect activation volume /spl upsi/. Calculated /spl upsi//sup 1/3/ values are approximately equal to the average grain size of the hard phase.