Directional Solidification in Air of NdBaCuO bulk Superconductor

NdBaCuO bulk samples have been fabricated by directional solidification in air using both top-seeding growth and horizontal Bridgman techniques. In order to avoid the substitution of Nd in Ba sites in the superconducting phase, the samples were prepared by admixtures of NdBa2Cu3O7 and a Nd-poor brown phase. Single-domain samples up to 1 centimetre have been obtained. Transition temperatures of about 90 K have been measured in samples annealed at low temperature in a pure oxygen atmosphere