Kondo-like effect in magnetoresistive CuCo alloys

Abstract

Electronic transport properties of twin roller melt spun Cu100−𝑥⁢Co𝑥 (𝑥=10,15) alloys, are investigated in the temperature range between 10 and 300 K. Negative magnetoresistance is observed up to 0.85 T in the as-cast state, which further increases with a treatment of 1 h at 923 K. Resistance exhibits a metallic behavior below room temperature and draws a minimum near 30 K in all the as-cast microstructures; this minimum diminishes when a magnetic field is applied and completely disappears after high-temperature annealing. A logarithmic dependence of the electric resistance on temperature is found below 30 K. A Kondo-like scattering mechanism involving small Co spin clusters is considered to explain the minimum.