Magnetic Properties of Amorphous Co-Base Films with Dispersed Fine Nitride

In efforts to obtain excellent-quality magnetic thin films for use in micro-inductance cores, amorphous Co-base films containing fine dispersed nitride particles were investigated. Sputter-deposited films were confirmed to have an amorphous structure, near-zero magnetostriction (¿) and high electrical resistivity. TEM observations clarified that films were composed of two kinds of amorphous phase. The soft magnetic properties of films were found to be related to the film thickness: at thicknesses below 0.1 ¿m, films became magnetically soft. Based on this relation, we attempted to prepare multilayered films consisting of thin Co-base layers and thin BN ceramic layers, and obtained excellent properties as a result, with a high ¿ (≫300 ¿¿-cm), low ¿ (1×10-6) and high ¿ (≫1000) at high frequencies near 100 MHz.