Compatibility of Nd and Ba in YBa2Cu3Oy superconductor

A series of samples with nominal compositions of YBa2-xNdxCu3Oy were prepared by solid state reactions and investigated by X-ray diffraction, magnetic and electrical measurements. The solubility, x, was determined to be x < 0.25. It is found that the solubility of rare earth Re ions at the Basites in Re1+xBa2-xCu3Oy is strongly related to a geometric parameter, the tolerance factor t. For x < 0.25, T-c0 are all above 92K. For x > 0.3 T-c0 drops sharply to about 84K, and finally for x=0.5 T-c(on) falls to 30K and T-c0 is below 10K. Our results suggest that the small compatibility of Nd and Ba in YBa2Cu3Oy system does not seriously suppress the superconductivity.