Particle size effect on the complex permeability for permalloy composite materials

Complex permeability mu*(=mu'-i mu ") Of permalloy (Fe0.55Ni0.45) composite materials has been studied in the frequency range from 10kHz to 2GHz for t wo different particle sizes of permalloys (particle diameter d<45 mu m and d<6 mu m). Low frequency permeabilities of small particle composites have l arger values than those of large particle ones and natural resonance freque ncy of small particle composites is lower than that of large particle ones. The ac electrical resistivity in low frequency range shows a drastic incre ase at about 40vol% permalloy content with decreasing permalloy content ind icating re disconnection of embedded permalloy particles. These properties can be realized considering the eddy current in composite materials.