Response Of Ybco Superconductor Doped With Strontium After Gamma Irradiation

Different compounds of Y-1 Ba2-xSxCu3O7-delta have been prepared in order to investigate the effect of gamma-irradiation and Sr substitution for Ba on the structure and physical properties of this superconductive system. X-ray measurements show that the samples with different Sr ratios were found to exhibit a single or nearly single superconducting 123 orthorhombic phase before irradiation, and exhibit multiphases after irradiations. The studied samples have the tendency to transform from orthorhombic to tetragonal structures with increasing Sr content. Also an overall slight reduction of the lattice parameters a, b and c is observed by the increasing of Sr content before and after irradiation. From a.c. magnetic susceptibility measurements, for the non-irradiated samples with different Sr contents, transitions with onset temperatures around 83 K were observed and the transition temperatures were found to decrease with increasing Sr content. After irradiation, an overall reduction of the Meissner volume fractions, and a further decrease in the transition temperatures were observed. The effect of different gamma doses on the sample with x = 0.2 was found to suppress the transition temperature and producing of multiphase structures.