Magnetization and Magneto-resistance in Y(Ba1-xSrx)2Cu3O7-{\delta} (x =   0.00 - 0.50) superconductor
  Here we present the magnetic properties and upper critical field (BC2) of polycrystalline Y(Ba1-xSrx)2Cu3O7-{\delta} superconductors, which are being determined through detailed ac/dc susceptibility and resistivity under magnetic field (RTH) study. All the samples are synthesized through solid state reaction route. Reduction in Meissner fraction (the ratio of field cooled to zero field cooled magnetization) is observed with increasing Sr content, suggesting occurrence of flux pining in the doped samples. The ac susceptibility and resistivity measurements reveal improved grain couplings in Sr substituted samples. Consequently the inter-grain critical current density (Jc), upturn curvature near the Tc in temperature dependence of upper critical field [BC2(T)], and BC2 are enhanced. Both Jc and BC2 increase in lower Sr substitution (up to x = 0.10) samples followed by decrease in higher doping due to degradation in effective pining and grain coupling. 
N. P. Liyanawaduge, Shiva Kumar Singh, Anuj Kumar, Rajveer Jha, B. S.   B Karunarathne and V. P. S. Awana
cond-mat.supr-con