Explicit and closed-form expressions for describing magnetic behaviors of uniaxial anisotropy materials

Abstract

We present explicit, analytic, and closed-form expressions for describing magnetic behaviors of materials having the magnetic anisotropy energy of K sin(2) theta. The functional forms of the expressions depend on the ratio of an applied field to an anisotropy field and the ratio of the lowest critical field, for a domain wall to nucleate or move, to the anisotropy field. The present expressions for functions of experimentally measurable quantities gave an elegant method of fitting the quantities to the torque measurement. Furthermore, they may be useful to analyze the ferromagnetic resonance experiment and to measure the distribution of magnetic properties of magnetic aggregates. (C) 2000 American Institute of Physics. [S0003- 6951(00)00104-2].