Chemical and magnetic phase diagrams of AB(3) and A(3)B anisotropic thin films

We present a double Ising model treated in the Bragg-Williams approximation with aim to describe the composition modulations and the magnetic properti es of MBE codeposited fee (111) oriented alloy thin films. First the chemic al and magnetic phase diagrams of isotropic AB(3) and A(3)B fee; structures with A the magnetic component are calculated. Then the effect of anisotrop ic chemical interactions that are different in the basic (111) planes and b etween these planes is investigated. It yields the formation of a superlatt ice-like system analogous to those experimentally observed in some Go-based alloy films. On the B-rich side, the magnetic phase diagrams are strongly modified with respect to the isotropic case. Comparison is made with experi mental data.