Mean-field Solution of the mixed spin-1 and spin-52Ising system with different single-ion anisotropies

Abstract EN

The mixed-spin ferrimagnetic Ising system consists of two-dimensional sublattices A and B with spin values  1 A s and  5/ 2 B s respectively .By used the mean-field approximation MFA of Ising model to find magnetism( B A m ,m ).In order to determined the best stabile magnetism , Gibbs free energy employ a variational method based on the Bogoliubov inequality .The ground-state (Phase diagram) structure of our system can easily be determined atT  0 , we find six phases with different spins values depend on the effect of a single-ion anisotropies B A D ,D .these lead to determined the second , first orders transition ,and the tricritical points as well as the compensation phenomenon