Abstract
High energy transmission electron diffraction and microscope studies have been made of the following rare earth metals, Gd, Tb, Dy, Ho, Er and Tm, the films being made by means of vapour deposition. The thinnest films had face centred cubic structures whereas in the thicker films the hexagonal close packed structures of the metals in bulk form were observed. Oxidation of the films was observed in the vacuum in which they were deposited and also under the influence of the electron beam of the electron microscope. The lattice parameters of the face centred cubic forms of Gd, Tb, Dy, Ho, Er and Tm were found respectively to be 5.40, 5.20, 5.18, 5.15, 5.09 and 5.06 AA the error being about +or-1%.