X-Ray Diffraction Study on the Crystal Structure of Nd1+xBa2-xCu3O7-δ

Abstract
Crystal structures in the Nd1+x Ba2-x Cu3O7-δ system have been investigated by X-ray powder diffraction combined with Rietveld analysis. The compound NdBa2Cu3O7-δ is isomorphic with orthorhombic YBa2Cu3O7-δ. With the increase of x the orthorhombic distortion decreases, and the compound becomes tetragonal at x=0.2. The tetragonal structure is isomorphic with the tetragonal form of YBa2Cu3O7-δ. T c of the compounds with x=0 and 0.05 is above 90 K, which decreases monotonically with x and the compound becomes semiconducting at x=0.4.