INHOMOGENEITIES AND SEGREGATION BEHAVIOR IN STRONTIUM-BARIUM NIOBATE FIBERS GROWN BY LASER-HEATED PEDESTAL GROWTH TECHNIQUE .2.

Inhomogeneities in Ce-doped and undoped fibers grown by laser-heated p edestal growth (LHPG) along the c- or a- axis were investigated by two -dimensional scanning electron microprobe analysis (SEPMA). SEPMA data indicated that these cores are primarily connected with the source ro d compositions utilized and the convection characteristics of the LHPG technique, Ba enrichment and Sr decrease were primarily detected in t he cores and qualitatively described in terms of the composition-contr ol mechanism of LHPG, the complex-segregation and a modified Burton-Pr im-Slichter (BPS) equation. Certain aspects of defect structure as a c omplex congruency related phenomenon are also discussed in the paper g iving a more complete interpretation of the origin of cores in SBN fib ers.