Effect of growth temperature on superconducting properties of YBa ₂Cu₃O_y bulk superconductors grown by seeded infiltration

We investigated the effect of growth temperature on the characteristics of YBa₂Cu₃O_y (Y-123) bulk superconductor prepared by seeded infiltration process. Homemade Y₂BaCuO₅ "Y-211" particles and liquid phase of Ba₃Cu ₅O₈ were used to produce Y-123 bulks in air such that the liquid phase infiltrates into a Y-211 block. Y-123 samples of 20 mm diameter and 8 mm thickness were produced at different growth temperatures, i.e., 990, 985, 983, 980 and 978 °C with the same holding time of 25 h. We found that single grain growth without multi-nucleation occurred at 980 °C. Further, magnetization measurements indicated a sharp superconducting transition with T_c (onset) around 93.2 K. Trapped field measurements showed that the samples are single domain, and the sample 27 mm in diameter and 5 mm in thickness showed the maximum trapped field of around 0.45 T on the sample surface at 77 K. The critical current density (J_c) at 77 K and zero field was determined to be 175 kA/cm², which is the highest value ever reported in the literature.