Monte Carlo simulations on thin rare earth films: Preliminary data

We present Monte Carlo simulation data about Holmium magnetic thin film structures. As well known, this rare earth shows, at transition temperature T N , a helical order in the bulk phase. In contrast with the collinear ferromagnetic or antiferromagnetic thin films, recent experimental works have proven that the transition temperature T N ( n ) ( n being the film thickness) depends on n only by an empirical relation. In order to study the behavior of these film structures, we consider a Heisenberg model with easy-plane single ion anisotropy and seven coupling constant ( J 0 in the plane and J 1 − J 6 between plane of the Ho h c p structure), obtained by experimental neutron measurements.