Flux pinning properties and superconductivity of Gd-123 superconductor with addition of nanosized SnO₂/ZrO₂ particles

By using top seeding melt-textured growth process, single domain bulk superconductor GdBa₂Cu₃O_7-δ (Gd-123) was prepared in air with variable additions of nanosized SnO₂ and ZrO₂ powders. The inhomogeneous distribution of Gd₂BaCuO₅ particles was observed by scanning electron microscope study for each bulk with nanoparticles addition. A band structure composed by second phase free band, narrow second phase rich band and second phase diluted band was observed along both a-b plane and c growth sectors in the vicinity of seed site. At 77 K high critical current (J_c) was increased up to 99,300 A cm^-2 under self-field in H∥c-axis configuration in Gd-123 bulk with 0.004 ZrO₂ addition, molar ratio to Gd-123. J_c has a remarkable spacial distribution inside the samples while keeping T_c almost stable for all addition quantities.