Enhancement of superconducting properties of textured YBCO using double seeded technique

Isothermal melt texturing is currently a well established technique for manufacturing superconducting bulk materials with high trapped magnetic fields and levitation forces. The technique involves the growth of RE-123 compounds in geometries such as discs and short rods using top seeding of high temperature material such as SmBCO. The technique is relatively simple, however it yields nonuniform microstructure and variable superconducting properties throughout the length of the sample. The top half of the sample is well oriented and possesses good properties, while the bottom half suffers from misorientation, porosity and poor superconducting properties. In this work, the effects of using top and bottom seeding on microstructure and crystal orientation were studied. We also measured trapped magnetic fields throughout the thickness of the sample. In this arrangement, we found that both top and bottom parts of the sample are well oriented and the trapped magnetic fields in both halves are almost the same. These results give promise to the use of this technique to improve the superconducting properties in bulk textured YBCO.