Hysteresis and relaxation effects in magnetic materials

The connection between hysteresis and time effects due to thermal relaxatio n is studied in the framework of hysteresis modeling. The system with hyste resis is described as the superposition of elementary contributions distrib uted in energy levels and energy barriers. A set of general laws, connectin g loop shapes and Lime relaxation patterns, are derived independently of th e details of the distributions. Limits and possible extensions of the appro ach are discussed in connection with simple models of the magnetization pro cess.