Abstract
Tc depressed with increasing Sr substitution in YBa 2-x Sr x Cu 3 O y system. However x-ray diffraction revealed monophase similar to the basic 1-2-3 structure persists for X up to 1.0. Extensive dislocation was observed for X=1 which seems associated with local variation of Sr/Ba atomic ratio and arrangement. © 1988 Elsevier Science Publishers B.V.