By using the differential operator technique and the effective field theory scheme we study the tricritical behavior of Heisenberg classical model of spin-12 in a random field. The phase diagram in the T–h plane on a square and simple cubic lattice for a cluster with two spins is obtained when...

In this work, a study on a site diluted Ising model system is applied to the magnetic properties of the bcc disordered phase of FeAl alloys by employing effective field theory. Here, one suggests a new approach to exchange interaction between nearest neighbors of Fe that depends on the powers of...