Voitenko T. Synthesis, structure, electrophysical properties and oxygen stoichiometry of cuprates rare-earth elements and bismuth.

The dissertation is devoted to optimization of conditions of the formations of cuprates based on rare-earth elements and bismuth and investigation dependence on chemical composition, electrophysical properties, oxygen stoichiometry and Tc.The Bi-contaning samples were synthesized using the ceramic technique with precursor, samples based on rare-earth elements were synthesized using sol-gel method. Dependence on parameters and kinds of lattice symmetry of GdLnxBa2 xCu3O7±z (Ln-Pr, Sm, Eu) from the displacement degree x was studied. It's adjusted that for solid solutions GdLnxBa2-xCu3O7±z (Ln-Pr, Sm, Eu) just substances with x=0 and x=0.05 have superconductivity properties in temperature interval 77-300 K. For Bi2Sr2Ca1-xLnxCu2Oу (Ln-La, Nd, Y, Ho, Lu), Bi2 xLnxSr2CaCu2O8+z (Ln-La, Nd, Y, Ho, Lu), Bi2 xLnxSr2CuO6+z (Ln-La, Nd, Y), Bi2Sr2CaCu2Oy +xA, (A-СaAl2O4, CaZrO3, Ca2Nb2O7) a homogeneity region, structural parameters, electrophysical properties, oxygen stoichiometry depend on their composition (x) and Tcon value was study. Shown, that the value of Tcon does not depend on the value of oxygen index z.