Synthesis of high-purity (CaxLa1.00-x)(Ba1.75-xLa0.25+x)Cu3Oz tetragonal superconductor by an aqueous solution technique using citric acid

A simple aqueous solution technique utilizing citric acid as a complexant w as applied to prepare (CaxLa1.00-x)-(Ba1.75-xLa0.25+x)Cu3O2. The combined r esults of X-ray diffraction and Raman scattering analysis confirmed the sin gle-phase character of polycrystalline sample for the whole range of x from 0.0 to 1.0. The Tc onset values, determined precisely from the complex mag netic susceptibility measurements, values increased from 40.6 K for x = 0.0 to 78.7 K for x = 0.4. remained almost constant at 80 K between x = 0.5 an d = 0.7, and then decreased to 44.6 K for x 1.0. (C) 2001 Elsevier Science B.V. All rights reserved.