Soft magnetic granular thin films with the plasma polymerized non-magnetic matrix

In this review a method for polymerization of fluorocarbon gas in argon plasma to obtain a novel granular structure was reported．We prepared granular films where FeCo fine particles were distributed in plasma-polymerized fluorocarbon matrix by a facing-targets rf magnetron sputtering method，and investigated the correlation between their structures and magnetic properties．The magnetization of the films prepared with the partial pressure of fluorocarbon gas between 0 and 1.0 mTorr decreased，because the FeCo content in a unit volume of a film decreased．However，the coercivity of the films decreased drastically with increasing the partial pressure of fluorocarbon gas above 0.4 mTorr． This is because the magnetic anisotropy of FeCo particles is decreased by the decrease of grain size．It was confirmed by a HR-SEM observation that the FeCo-(C4F8)n films had the granular structure which was constituted by the very fine FeCo particles and the plasma-polymerized fluorocarbon matrix