Wide frequency complex permeability function for linear magnetic materials

A mathematical model is presented in which both the energy loss, the reactive power and the complex permeability of soft magnetic material cores are described in a wide frequency range. This general function is based on impedance functions and on the theory of one-dimensional homogeneous transmission lines. Besides the three material parameters (thickness, density and electrical conductivity), only four fitting parameters are used in the model. A good correspondence has been found for the description of a variety of soft magnetic materials. A comparison of the model prediction with experimental data is presented for toroidal nanocrystalline cores.