抄録
The magnetoresistance (MR) effect of noble metal based Fe granular thin films has been investigated from the stand point of the magnetic cluster distribution in the film. Samples of Cu1-xFex and Au1-xFex were prepared by an ion beam sputtering metod. The MR ratios as a function of Fe content in Cu and Au matrices show maximum values around x=0.12 and 0.24, respectively. The number of Fe atoms belonging to the superparamagnetic clusters has been estimated from the analysis of magnetization curves. The MR ratio increased with the number of Fe atoms responsible for superparamagnetism per unit volume. This tendency can be explained by an universal curve for both systems. The MR ratio decreases with increasing temperature, but it remained around the Curie temperature (Tc). It is considered that this behavior is due to the increase of superparamagnetic Fe clusters around Tc.
