Metallic spin-glasses beyond mean-field: an approach to the impurity-concentration dependence of the freezing temperature.

A relation between the freezing temperature (T(g)) and the exchange couplings (J(ij)) in metallic spin-glasses is derived, taking the spin correlations (C(ij)) into account. This approach does not involve a disorder average. The expansion of the correlations to first order in J(ij)/T(g) leads to the molecular-field result from Thouless-Anderson-Palmer. Employing the current theory for the spin interaction in disordered metals, an equation for T(g) as a function of the concentration of impurities is obtained, which reproduces the available data from AuFe, AgMn, and CuMn alloys well.