Concentration Dependence of the Anomalous Thermoelectric Power of Dilute Magnetic Alloys

It has been pointed out recently by one of us (M.S.R.C.) that the variation of the Kondo slopes d (of the rho/c vs. In T curves) of dilute magnetic alloys containing a finite solute concentration c bears a close resemblance to the variation of the function f (= cos(6) eta cos 2 eta) with the phase shift eta for ordinary spin-independent scattering. Since d is itself primarily determined by f the inference is that eta is a function of c when the criterion of infinite dilution is violated. For infinite dilutions theory expects the anomalous thermoelectric power in such alloys to be independent of c as well as of T. Taking the experimentally observed extremum in the TEP (S-m) as an approximation to such a TEP, we report, for finite solute concentrations, the variation of S-m with c, to correspond with the variation of f'(= cos(6) eta sin 2 eta) with eta. This substantiates the above inference. In fact, one can predict the sign and the variation (with c) of d, knowing that of S-m, and vice versa, for a given dilute magnetic alloy system.