Abstract
Granular alloy films CoxCu1-x (0.17 ≤ x ≤ 0.66) were prepared by pulse plating. Although a second phase, probably hexagonal close-packed phase, was present in the X-ray diffraction pattern for all samples examined, the matrices showed the face-centered cubic lattice parameter decreasing almost linearly with increasing x. The magnetoresistance (MR) of films was found to be larger after annealing at an appropriate temperature between 400°C and 600°C. A maximum value of the MR ratio of about 4.2% was observed at the composition around x = 0.2. The remanence ratio was found to be 0.4-0.6 for all films measured, indicating the presence of ferromagnetically interacting particles even in the as-deposited condition and to depend little on the composition. The average size of magnetic particle D for x = 0.31 estimated using M(H) data at room temperature was found to be about 9.7 nm before annealing and 12 nm after annealing at 450°C. The large magnetic particle size in the as-deposited state seems to be the main cause of the small MR value.
