Temperature dependence of hysteresis and relaxation effects in hard magnetic materials

Abstract Hysteresis properties and viscosity effects have been studied at several temperatures (in the range from 140 to 500 K) on hard Sm(Co,Cu) 5 alloys. The application of a recently proposed theoretical approach permits one to identify the fluctuation field H f , connected to a typical activation volume, and the Preisach distribution, connected to microstructure. We found that: (i) at a single temperature, the model is able to reproduce the complex magnetization dynamics measured under pulsed field history excitation in a detailed fashion; (ii) the Preisach distribution for different temperatures can be rescaled onto a temperature-independent single curve through a temperature-dependent scale factor H A ( T ) equivalent to the anisotropy field.