X-RAY STUDIES OF SAPPHIRE CRYSTAL PERFECTION.
Scientific rept. no. 1, (Final) 1 Sep-30 Nov 63
MANLABS INC CAMBRIDGE MASS
Pagination or Media Count:
The imperfection structure of A1203 single crystals was studied with the double crystal X-ray spectrometer. Preliminary rocking curve measurements on the basal planes of several sapphire and crystals indicated a dependence of peak multiplicity on rocking axis orientation. The results could be interpreted in terms of an ordered stacking of line dislocations having the 1120 Burgers vector. A pair of fully oriented 0 and 90 degree Verneuil crystals were examined by light microscopy, Laue back reflection photography and diffraction techniques, revealing major differences in imperfection structure between the two crystals. Detailed rocking curve surveys of the principal planes of the 90 degree crystal were made and dislocation densities calculated from the measured half-breadths in terms of proposed dislocation models. Good agreement is found between the calculated dislocation densities and those determined by etch pit counting. Author