Magnetic phase transitions of ultra-thin Fe films

Magnetic properties of ultra-thin Fe(100) films are studied experimentally, with an emphasis on the temperature dependence of the magnetization and the influence of the substrate on magnetic properties. It is found that the nature and orientation of the substrate, here Au(100) and Pd(100), have significant effects on the character of the ferromagnetic phase transition, in particular the thermodynamic behavior near the Curie point is strongly dependent on the details of the system, in contrast to the case of bulk Fe. These results are consistent with predictions for the XY model with crystalline anisotropies