Zelen'ko M. Synthesis and properties of high-temperature superconductors based on the thallium and rare-earth elements

The dissertation is devoted to optimization of generation of superconductors based on rare earth elements and thallium, as well as to discovery and research of relationships between their chemical composition, electrophysical properties and thermal treatment conditions. It was indicated that the solid-phase method with prior precursor preparation is the best synthesis method for thallium-containing compounds. There were composition of LnBa2Cu4O8, Ln-Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu specimens defined, and the character of changes of ionic radii, critical parameters and symmetry type of crystal lattice depending on the composition was investigated. For specimens of Tl2-xBixBa2Ca2Cu3Ox, Tl1-xBixBa2Ca2Cu3Ox, Tl2М0.2Ba2CaCu2Oх (М - Zr, Pb), the influence of alloying additions on electrophysical properties and structural parameters was researched. There was the influence of alloying additions on processes of chemical degradation of high temperature superconducting ceramics under the effect of water and water vapor researched. It was indicated that injection of bismuth, zirconium and lead has different influence on ceramics specimens' persistency.