Pozigun S. Metal-oxide compounds Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O and connection of their microstructure with the high superconducting parameters

The influence of different methods of treatment and synthesis on the superconducting properties, structure and morphology of polycrystal and film samples based on Y, Bi and Tl is studied. It is shown that the pulsed plasma is able to increase effectively both the critical temperature and critical current of HTSC samples and also to create new superconducting phases. The analysis of heat balance of the plasma process treatment is made. It is shown that due to the MOCVD method it is possible to synthesize the epitaxial YBCO films with the recordly high superconducting parameters. The dependence Hc2(Tc) is obtained for the film samples and the value of coherence length 40 A is received. The magnetic properties of YBCO single crystal, (Y,Th)-Ba-Cu-O polycrystals and Bi-2223 polycrystals are investigated.