Fabrication of neodymium-based superconducting bulk materials

We report on Nd123 bulk samples directionally solidified in air prepared wi th Ba-rich Nd422 doping brown phase by top seeding growth (TSG). By using t his technique, we have fabricated single domain pellets up to 3.5 cm of dia meter and 1 cm of thickness. The crystallographic alignment and the texture of samples have been investigated by means of polarised light optical micr oscopy, scanning electron microscope, supplemented by energy dispersive spe ctroscopy and X-ray diffraction analysis. The resulting microstructures hav e shown Nd1Ba2Cu3O6+d domains, and Nd4Ba2Cu2O10-d particles' size distribut ion, depending on the used values of the fabrication process's parameters. In particular, we investigated the influence both of the growth temperature window and of the cooling rate on the growth dynamics of the samples and o n the precipitates segregation mechanism was analysed.