The growth and structure of epitaxial films of the rare-earth dihydrides

Abstract

Thin films have been grown on the cubic, dodecahedral and octahedral faces of rock salt by vacuum evaporation, at 10-6 and 10-10 Torr, of Gd, Tb, Dy, Er and Ho, and their structures have been examined by electron microscopy and diffraction. Conditions have been established for the epitaxial growth of the rare-earth dihydride films in the thickness range up to approximately 25 nm. Between 25 and 20 nm a mixed phase of FCC dihydride and HCP metal is formed, and above 90 nm the films are substantially metallic. Reflection electron diffraction and hydrogen annealing experiments suggest that the formation of the dihydride may be influenced by adsorbed hydrogen on the substrates.