Neodymium as a dopant in top-seeding-melt-texture-growth-processed YBa2Cu3O7−δ ceramics

Abstract

The effects of Nd2O3 doping (from 0.25 to 1% wt of Nd2O3) of top-seeding-melt-texture-growth-processed YBa2Cu3O7−δ (Y123) ceramics are investigated. The texturing thermal cycle of the pellets is similar to the one used to texture neodymium-free Y123 samples. The SEM study of the microstructures of the doped samples does not show significant differences compared to those of textured neodymium-free Y123 samples; the size of the Y2Ba1Cu1O5 particles (Y211) does not change and no secondary phase appears. From EDS analysis, neodymium is found in both the Y123 matrix and the Y211 particles (about 1.80% atom of neodymium in the Y211 particles and about 0.7% atom of neodymium in the Y123 matrix for 1% wt of Nd2O3). After the usual oxygen annealing process used for neodymium-free Y123 samples, the samples show poor superconducting properties. A second similar annealing does not improve these properties. A new annealing process at lower temperatures (between 430 and 300 °C) leads to samples with good superconducting properties, but only similar to those usually observed for neodymium undoped compositions.