Table 980. Electron diffraction of gadolinium silicides.
Coexistence of epitaxial H(hexagonal)-GdSi2-x and polycrystalline O(orthorhombic)-GdSi2 in a Gd/(001)Si sample annealed at 600 °C: (a) polycrystalline O-GdSi2 rings and two sets of epitaxial H-GdSi2-x (see page2036_f), with orientation relationships between H-GdSi2-x and (001)Si, which are (A) (1-100)GdSi2-x/(001)Si with GdSi2-x/[2-20]Si and (B) (1-100)GdSi2-x/(001)Si with [11-20]-GdSi2-x/[2-20]Si. The two sets of GdSi2-x are crystallographically equivalent with one rotating 90° relative to the other around the common [1-100]GdSi2-x axis. Two perpendicular
orientations with the same Moire fringe spacings, indicating that the epitaxial films tend to orient with two different azimuthal orientations rotated by 90° with each other. 
 J.C. Chen, G.H. Shen, L.J. Chen, Interfacial reactions of Gd thin films on (111) and (001) Si, Applied Surface Science 142 (1999) 291–294.