LOW-TEMPERATURE RESISTIVITY IN A GIANT MOMENT ALLOY

Resistivity measurements have been made on a dilute alloy of 0.07 at.% Co in Pt in the temperature range of 1.0 to 20°K. We find that the net resistivity, ρalloy-ρpurePt, is linearly proportional to +lnT in this temperature range, in accordance with Kondo's s-d exchange scattering theory when the effect of ordinary scattering is taken into account. We also find that the net resistivity is linearly proportional to μeff(T)2, where μeff(T) is the effective moment associated with the Co impurity and surrounding Pt electrons, which decreases at lower temperatures, as deduced from Pt195 nuclear-magnetic-resonance linewidth measurements in the same system. This kind of behavior is predicted by Knapp's two-band model. © 1969 The American Physical Society.