Abstract
A diluted fcc magnet with modified long-range Ruderman–Kittel–Kasuya–Yosida interaction and arbitrary Ising spin is considered within a two-sublattice model. The exponential damping for the long-range interaction as well as the nearest-neighbor antiferromagnetic superexchange couplings are taken into account. In the molecular field approximation, the Gibbs free energy is derived, from which all magnetic thermodynamic properties can be self-consistently obtained. In particular, the phase diagrams are studied for different magnetic ion and free charge carrier concentrations, taking into account the atomic short-range-order (Warren–Cowley) parameter and the external magnetic field. The stability regions of paramagnetic, ferromagnetic, and three characteristic antiferromagnetic phases are discussed. Moreover, the critical temperature and degree of magnetic frustration are evaluated to be dependent on the short-range order.
2 More- Received 10 December 2007
DOI:https://doi.org/10.1103/PhysRevB.77.115204
©2008 American Physical Society