Use of the polysaccharide dextran as a morphological directing agent in the synthesis of high-Tc superconducting YBa2Cu3O7-δ sponges with improved critical current densities

Preparation of YBa2Cu3O7- ω (Y123) sponges by the admixing of dextran with a solution of metal nitrate salts of the correct stoichiometry to form Y123 was investigated. Sponges were prepared by the addition of dextran to a superconductor precursor solution. Calcination was performed on silver-doped samples and sodium-doped Y123 sponges was prepared by sprinkling finely ground NaCl across the surface of the hardened Y123-dextran composite paste prior to calcination. Samples for scanning electron microscopy were prepared by mounting on aluminum stubs and sputter coating with platinum prior to observation. Results show that by performing an in-air calcination of Y123 in the presence of the polysaccharide dextran, sponge-like architectures of super-conducting material are produced.