STUDY OF STRUCTURAL HETEROGENEITY OF HTSC BI-CERAMICS

Using Bi-ceramics as an example, we estimate here the possibility of d etermination of the structural heterogeneity of HTSC materials from X- ray powder diffraction data. The heterogeneity is due to the presence of alternating layers of different types within individual microcrysta ls. Explicit information on alternating fragments of different height is provided by the intensity distribution data of basal reflections, t herefore we studied X-ray diffraction patterns of oriented specimens. The diffraction patterns from unidimensionally disordered structures w ere simulated based on a previously devised procedure for the calculat ion of diffraction profiles of mixed-layer minerals. The comparison of calculated and experimental diffraction patterns testifies that defec ts in the samples are really caused by the presence of layers of diffe rent heights corresponding to the 2212 phase built into the matrix of the basic 2223 phase. The concentration of such defects reaches 20% wi th a high segregation degree of both layer types.