Top Seeded Melt-Grown bulk YBa₂Cu₃O_y superconductors can be used as trapped field magnets in various industrial applications. There a uniform performance of the material is crucial. In the present study, we prepared two bulk YBa₂Cu₃O_y superconductors by top seeded melt growth (TSMG) and top seeded Infiltration Growth (TSIG) techniques. Trapped field measurement at 77 K showed a single-domain nature of both samples. We studied the variation of superconducting properties along c-axis of the pellet, cutting a vertical 2 mm thick slice from the center of the 20 mm in diameter single-grain Y-123 pellet. From this, we cut six small pieces, 3 from the top and 3 from the middle, and studied systematically their X-ray diffraction, superconducting performance, T_c and J_c, by SQUID magnetometer, and microstructure by scanning electron microscopy (SEM). Then we compared the results. The critical current density values for TSMG or TSIG samples depended on the Y-211 secondary particle dispersion. The J_c value is explained based on the micro structural analysis.

Keywords: YBa2Cu3Oy, TSMG and TSIG, critical current density, scanning electron microscopy