Single impurity Kondo effect in gold: I. Thermopower

Abstract

The resistivity and thermopower of a sample of gold containing initially 13 ppm Fe have been measured as a function of Fe concentration. This was systematically reduced by a treatment with chlorine at 800 degrees C. For each 4 h treatment time the Fe concentration decreased roughly by a factor of 10. In 16 h the concentration had been reduced from 13 to 10-3 ppm, the resistivity from 14.4 to 4.0 n Omega cm and the thermopower from -7.2 to +0.03 mu V K-1. The transition from a typical dilute magnetic alloy to a typical pure metal has been followed in detail and agreement with single impurity Kondo effect theory is good.