Kondo-like behavior and GMR effect in granular Cu90Co10 microwires

Abstract

We observed a significant increase of the giant magnetoresistance (GMR) effect (up to 32% after the adequate annealing) and Kondo-like behavior in Cu90Co10 glass-coated microwires. Observed enhancement of the GMR effect can be interpreted considering the formation of the fine Co grains inside the Cu matrix as well as appearance of lamellar nanostructures allowing enhancement of the MR effect after annealing. Observed experimental data are discussed considering the regions with higher Co-ions content responsible for the presence of Co inhomogeneities or clusters and the regions with lower Co-ions content behaving as the magnetic impurities in the metallic host. Observed resistivity minimum on temperature dependence can be described considering Kondo effect mechanism involving magnetic impurities in metals. But the other mechanisms responsible for the resistivity minimum have been considered.