Theory of the magnetization and exchange-enhanced susceptibility of alloys. II. Zero-temperature magnetization and susceptibility in the presence of moments

A theoretical treatment of the zero-temperature exchange-enhanced susceptibility of paramagnetic substitutionally disordered alloys within the random-phase approximation was presented in the preceding paper (I of this series). In the present paper that treatment is extended so as to allow the calculation of the local susceptibility in the presence of moments and/or large applied magnetic fields and the calculation of the spontaneous and induced local magnetization. The cluster treatment presented here is the first cluster theory to treat quantitatively the effect of moment formation on the local susceptibility. Moreover, the techniques presented here are computationally feasible even for the study of concentrated alloys and yield results for the size of local moments as a function of their local environment. Interpolation schemes which allow one to calculate easily the magnetization and local susceptibility associated with any magnetic cluster configuration also are presented. The use of the formalism presented is illustrated by applying it to the calculation of the magnetization and susceptibility of different configurations of Ni atoms embedded in Pd and in exchange-enhanced effective media.