Processing and levitation force in top-seeded YBCO

Bulk cylinders of YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ composites, up to 35.0 mm in diameter, have been melt-processed using MgO single crystals, Nd123 and Sm123 melt textured ceramics, as seeds. The influence of processing parameters has been examined in order to optimize the growth conditions. Polarized light microscopy, SEM and EDX, have been used to characterize the orientation, size and morphology of the grains, as well as the spatial distribution and size of Y211 particles. An increase of the levitation forces is observed when the top seeding growth is carried out under a temperature gradient. The trapped magnetic and the levitation force of a single domain sample was systematically measured and theoretically simulated by finite element calculations. The deduced J/sub c/ from the different experiments have been compared and analyzed.