LAUSR

Abstract Using a microscopic model and the Green’s function technique we have studied the influence of different surface, size and substrate effects on the magnetic properties of BaCoF 4 thin films. The magnetization and the magnetic phase transition temperature increase for a compressible substrate Al 2 O 3 , whereas they decrease for a tensile substrate such as MgO. The film thickness influences also the magnetic properties. We have discussed a competition, a concurrence between the surface and substrate effects. Doping of bulk BaCoF 4 with Al ions leads to weak room temperature ferromagnetism. Due to the magnetoelectric coupling is obtained that the polarization increases with increasing external magnetic field.