Effect of the composition and process on the Nd1Ba2Cu3Oy bulk properties in oxygen-controlled melt growth synthesis

Nd1+xBa2−xCu3Oy bulk superconductors have been synthesised by the oxygen-controlled melt growth method (OCMG). The texturing thermal cycle of the pellets has been optimised and the influence of the support determined. Then, the effects of Nd4Ba2Cu2O10 and Nd3.6 Ba2.4Cu1.8O9.6 additions and Ce, Sn and Ag dopants on the microstructure and the superconducting properties have been tested. Under low field, good properties are obtained due to the refinement of the secondary phases. An oxygen-annealing with 600°C steps has been investigated. To improve superconducting properties under high field, a cooling rate of 1°C h−1 during 20°C after the nucleation window has a benefit effect.