Preparation and microstructures of CoAg granular films with giant magnetoresistance

A series of Co _x Ag_1–x (0 x < 100 at.%) granular films were deposited onto glass substrates with the thickness on the order of 400 nm using the ion-beam cosputtering technique at different substrate temperatures. Systematical investigations were made on the Giant MagnetoResistance (GMR) effect and microstructures in these thin granular films. The magnetoresistance ratio strongly depends on cobalt concentration, substrate temperature, and the optimal value of GMR was observed in Co₂₂Ag₇₈ sample prepared at a temperature of 300 K. Microstructures of these films are closely related to the fabricating process, and thus influence the GMR.