X-RAY TOPOGRAPHIC ASSESSMENT OF DEFECTS IN PURE AND SUBSTITUTED HEXAFERRITE CRYSTALS

Results of X-ray diffraction topography, in reflection and transmissio n scanning geometry, of flux grown single crystals of substituted and unsubstituted hexaferrites bearing composition SrGaxInyFe12-(x+y)O-19 (where x = 0, 5, 7, 9; y = 0, 0.8, 1.3, 1.0) are presented. Diffractio n topographs reveal defects like misoriented grains, dislocations, cav ities; inclusions, and the strain pat terns in these crystals. The uns ubstituted hexaferrites exhibit better perfection when compared to the substituted ones. The study is reported to support the results obtain ed by chemical etching and fractography, besides yielding additional i nformation covering defects.