Spin-glass behavior in dilute magnetic alloys with hcp structure

A simple physical model is presented for calculating the magnetization of dilute magnetic systems with hep hosts which incorporates elements of both crystal-field theory and the molecular-field theory of spin-glasses. To permit the computation of the Ruderman-Kittel-Kasuya-Yosida contribution, the interaction between the impurities is described by a randomly oriented effective internal exchange field h with a probability distribution P(h) = ∆/7π2(∆2+h2)2 , where A is the most probable value of the internal field. The observed crystal-field effects are analyzed in terms of an ionic fine-structure Hamiltonian of the form DSz, with the fine-structure parameter D proportional to spin-orbit coupling to second order. The model is used to account for the measured magnetization of both single-crystal MgMn and poly crystalline ZnMn alloys.