Determination of the intragrain critical current density and thermogravimetric analysis on YBCO/Ag superconductors irradiated with Co-60 gamma rays

We investigated the flux pinning behavior induced by gamma irradiation in Y 1Ba2Cu3O(7-x) silver-added samples. The superconductors were prepared throu gh solid-state route and added with silver in amounts of 0-, 6.5-, and 20-w t%, following which the samples were irradiated by high-energy gamma irradi ation (gamma) at doses of 0, 500, and 1500 kGy at the dosage rate of 8.2 kG y/h. We performed magnetization loops to study the flux pinning of vortex i n YBCO/Ag superconductors. We found that silver addition and irradiation on superconductors may increase the width in magnetization loops, which is re lated to the enhancement in the critical current density, J(c). We establis hed that an interaction between silver addition and irradiation that result s in higher values in J(c) for YBCO/Ag irradiated samples already exists. T he J(c) in samples containing 20-wt% of silver decreased with irradiation b ecause a higher content of silver produces small crystals and secondary pha ses growing. On comparing the TGA analysis for both YBCO and YBCO/Ag sample s, we found higher-weight oxygen losses in YBCO silver samples, which sugge sts that silver increases the oxygen saturation content. The higher oxygen content found on irradiated specimens it is indicative of oxygen losses fro m CuO chains or CuO2 planes reached by gamma-irradiation.