Statistical modeling of magnetic and magnetostrictive properties due to domain wall motion

Statistical mechanics is employed to derive magnetic and magnetostrictive b ulk properties of soft magnetic materials dominated by domain wall motion. The material is divided into an ensemble of volumes with uniform magnetizat ion, each one much smaller than a typical domain but much larger than one a tom. The energy for such a volume element is assumed to consist of an inter nal energy: the interaction with the external magnetic field and a mean fie ld interaction with the surrounding medium. The volume fractions of discret e mesoscopic magnetizations in the medium are derived from Boltzmann statis tics. The bulk magnetization is the weighted average of the mesoscopic valu es. Magnetostriction is treated in a similar way. Calculations are compared with two-dimensional measurements on grain-oriented silicon-iron. (C) 1999 American Institute of Physics. [S0021-8979(99)77008-8].