APPLICATION OF CYLINDRICAL CORRELATION-FUNCTIONS TO ANISOTROPIC SCATTERING FROM AMORPHOUS FILMS

The cylindrical pair correlation function has been utilized as a struc tural tool in the study of anisotropic phase separation in magnetron s puttered amorphous FexGe100-x films. Anomalous small-angle x-ray scatt ering (ASAXS) measurements have been performed with the scattering vec tor both in and oblique to the plane of the films, to search for aniso tropy. The cylindrical correlation function has been calculated from t hese measurements and indicates that there exist well-defined regions of electron density that are elongated (7 angstrom by 12 angstrom) in the direction of film growth. In addition, for a composition of x=6, t hese regions are well-correlated on a length scale of 27 angstrom for those correlation vectors oriented in the plane of the film surface, w hereas the correlations are far weaker and longer in length for those vectors aligned in the direction of growth, These results are in agree ment with a previous qualitative model of packed, prolate ellipsoids o riented in the direction of growth.