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 GdBa2Cu3O7−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 (Jc) 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. Jc has a remarkable spacial distribution inside the samples while keeping Tc almost stable for all addition quantities.