Magnetoresistance in bulk Cu-Co based alloys

An enhanced magnetoresistance of up to 11% at room temperature is found in granular Cu
_1-x
Co
_x
(0.1≤x≤0.5) alloys, which are prepared by melt-spinning and a subsequent annealing treatment. The rapid solidification extends the solubility of Co in Cu, i.e., the as-quenched state consists of a supersaturated Cu matrix with some quenched-in Co-precipitates. During subsequent heat treatment, the size and the density of the precipitates can be varied. Since the precipitates behave super paramagnetically at room temperature, the average particle sizes and the amount of precipitated Co can be estimated from magnetization curves.