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

Abstract

A relation between the freezing temperature ($T_{\mathrm{g}}^{}$) and the exchange couplings ($J_{ij}^{}$) in metallic spin-glasses is derived, taking the spin-correlations ($G_{ij}^{}$) into account. This approach does not involve a disorder-average. The expansion of the correlations to first order in $J_{ij}^{}/T_{\mathrm{g}}^{}$ leads to the molecular-field result from Thouless-Anderson-Palmer. Employing the current theory of the spin-interaction in disordered metals, an equation for $T_{\mathrm{g}}^{}$ as a function of the concentration of impurities is obtained, which reproduces the available data from {\sl Au}Fe, {\sl Ag}Mn, and {\sl Cu}Mn alloys well.

4 figures. This is a strongly revised version, where several aspects have been improved, and the equation for the freezing temperature has been refined. It is equivalent to the published version in J. Phys.: Condens. Matter 25 (2013) 136006

References in corpus (3)

• The large deviation approach to statistical mechanics
• Special invited paper. Large deviations
• Critical behavior and universality in Levy spin glasses