Electron-localisation effects on impurity dynamics. I. Kondo impurity

The Kondo effect in a disordered medium is investigated. The existing perturbation theories for static impurities and for magnetic ones are unified and examined in leading logarithmic order. When determining T_K the competition of two effects are shown: the decrease of the density of states at E_F decreases T_K; diffusive processes increase it. T_K depends in a non-monotonic way on the disorder. The experimental situation is discussed for both dilute magnetic alloys and metallic glasses.