High field magneto-transport and magnetization study of Y1−xCaxBa2Cu3O7-δO7-δ (x = 0.00–0.25)

We report DC isothermal magnetization, global critical current density (JC  ), Intra-grain critical current density (Jcintra) and resistive upper critical field (Bc2) of polycrystalline Y1−xCaxBa2Cu3O7−δ (YBCO); x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25. Ca doping at Y sites in YBCO superconductor results in flux pinning property, which can enhance the critical current densities and upper critical fields. JC   and Jcintra are experimentally calculated through DC isothermal magnetization measurement (M–H), employing the well known Bean’s critical model. It is observed that both type of current densities (global and intra) enhance in lower doped (5%) samples and can be accounted in terms of reaching maximum of pinning centers and improved grain couplings nature. The upper critical field (Bc2) increases with Ca content being consistent with enhanced grain coupling nature of doped samples.

► DC magnetization and high field magneto-transport for Ca doped YBCO is presented. ► Critical current densities of YBCO enhance for lower doped (approximately 5%). ► Enhancement in critical densities in terms of reaching maximum of pinning centres. ► An improvement in upper critical field was observed in Ca doped samples. ► Consistent with enhance grain coupling nature along with improved pinning behaviour.