Structure formation in Gd-Fe thin films

The structure, thermal stability and kinetics of phase transformations were explored for films of Gd2Fe17 compounds. The films were obtained by means of thermal evaporation in vacuum. Amorphous films were found to form at room temperature of substrates, amorphous-crystal condensates at Ts = 300-500 K, and polycrystalline films at Ts > 500 K. The crystal structure of condensates was determined at various temperatures and crystallization of amorphous films was found to be heterogeneous in character. Two phases, Gd6Fe23 and a-Fe, were observed in polycrystalline films, while three phases were found to exist in the films obtained at substrate temperatures >500 K: a hexagonal Gd2Fe17 phase of the Th2Ni17 structural type, a rhombohedral Gd2Fe17 phase of the Th2Zn17 structural type and a hexagonal GdFe5 phase of the CaCu5 structural type.