A Study of the High-Frequency Magnetic Properties of CoZrNb/SiO2 Multilayer Films

This paper reports on the design of a magnetic multilayer film with high permeability and low loss in the 1 MHz to 1 GHz range. The thickness of each layer and the magnetic anisotropy were optimized with respect to the eddy current loss and ferromagnetic resonance in the magnetic layers, and with respect to the dielectric breakdown in the nonmagnetic insulating layers. A limit relation for the product of permeability ¿´r(0) and the cutoff frequency fc was analyzed. The limit ¿´r(0)xfc is expected to have a much higher value than Snoek´s limit. A value for ¿´r of 300 was achieved in the range from 1 MHz to 1 GHz in an optimized CoZrNb/SiO2 multilayer film.