FORMULATION OF FREQUENCY DISPERSION OF FERRITE PERMEABILITY.

An empirical formula for the ferrite loss which best fits a number of observed data is derived for various types of ferrite. With the aid of the Kramers-Kronig relation, the real part of the ferrite permeability is found and relations among parameters involved in the complex ferrite permeability thus derived are discussed. The formula for the derived ferrite permeability is decomposed into two terms by considering the effect of a dc magnetic field; one for the spin rotation and another for the domain wall motion. The present formula contains six parameters. Given the proper values to these parameters, this formula enables one to approximate observed values of ferrite permeability over a very wide range of frequencies.