(Co-Ti-O)/Bi-Ti-O Multilayer Films with High-Frequency Electromagnetic Response

A series of (Co-Ti-O)/Bi-Ti-O multilayer films with 1-65 Co-Ti-O magnetic layers (MLs) are prepared by tandem sputtering method. The effects of the multilayers on the electromagnetic responses were investigated in the frequency range from 0.1 to 10 GHz. The multilayer films demonstrate soft-magnetic performance, maintain low loss of permeability (mu) up to a few GHz, and exhibit a clear peak of mu '' at their resonance frequency (f(r)). f(r) increase from 1.9 to 4.7 GHz with increasing MLs from 1 to 65. The multilayer films show a notable indentation of susceptance (B) at approximately f(r), which is not observed in a Bi-Ti-O monolayer film. (C) 2013 The Japan Society of Applied Physics