Thermodynamical properties of a mixed Ising ferromagnet system

Abstract

The critical behavior of a mixed ferromagnetic Ising spin system consisting of spin −1 2 and spin −1, with a single-ion uniaxial crystal field included, is studied by the use of a newly developed effective-field theory. The nature of the phase diagram is analysed for square and honeycomb lattices and comparison with a special exact solution and other approximation schemes are made.