Functional integral approach for temperature dependence of the magnetic hyperfine field at a Cd site in RCd (R = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er)

Abstract

A theoretical study of the local moment formation and of the magnetic hyperfine field at a non-magnetic s-p site, namely Cd, embedded in RCd (R = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) compounds is reported. The functional integral approach in the static approximation is adopted to calculate the temperature dependence of the local magnetic moments and hyperfine magnetic interactions, which is an extension of conventional mean field approach. Our calculations are performed in the temperature range from T=0K up to the critical temperatures TC of each compound, when they become paramagnetic. The local magnetic moments at a Cd, as a function of the temperature, were calculated from the perturbed densities of states. The results of our self-consistent calculations for the magnetic hyperfine field at the impurity site are in very good agreement with recent experimental reports. Furthermore, at T=0 K our results are compared with those obtained from ab initio calculations.