Magnetic-Field- and Temperature-Dependent Characteristics of Fe/Cu Granular Films Produced by Sputter- and Cluster-Beam-Deposition(Research in High Magnetic Fields)
The magnetoresistance (MR) and magnetization (M) have been measured as functions of temperature, T, and magnetic field, H, in sputter(SP)- and cluster-beam(CB)-deposited Fe_XCu_ alloys. The MR for the SP-deposited Fe_Cu_ film exhibits a maximum at around the Curie temperature (T_C=150 K) and increases rapidly below 100 K owing to a spin-glass transition. For the CB-deposited granular Fe-Cu films with low Fe content, the MR is also enhanced at low temperatures being attributable to a cluster-glass behavior of small fcc Fe clusters. At low temperatures, moreover, a T^ dependence is found for both MR and M versus T curves. For the SP-deposited Fe_Cu_ sample, the T^ coefficient of the MR roughly corresponds with that of the M. For the CB-deposited Fe_Cu_ sample, however, they are inconsistent each other. These results originate from different status of the Fe atoms : the Fe atoms are rather randomly dispersed in the Cu matrices in the SP-deposited sample, while they form clusters in the CB-deposited one
