Giant magnetoresistance in Co-Cu granular alloy films and nanowires prepared by pulsed-electrodeposition

摘要

Granular Co{sub}xCu{sub}(1-x) alloy films and nanowires were prepared by pulsed-electrodeposition. The alloy composition was changed by controlling pulse-width of the current pulse with fixed off-time of the deposition. Alloy films were formedonto evaporated Cu films grown on glass plates. The face-centered cubic lattice parameter was found to decrease with increasing Co content in the films in the composition range investigated (0.17≤x≤0.66), and the second phase, probably by hexagonalclose-packed phase, appeared at x≥0.42. The crystallite size of the as-deposited condition calculated using the XRD data and the Scherrer's formula ranged between 10-30 nm. The magnetoresistance (MR) was found to become larger after annealing at anappropriate temperature between 400-600℃. The maximum value of the MR ratio of about 4% was observed at the composition around x = 0.2. Magnetic hysteresis curves were measured for Co{sub}0.31Cu{sub}0.69 and compared with those reported for sputteredalloy films. Granular nanowires prepared into the pores of the alumite plate were also examined and reported briefly.