Manifestation of the effect of atomic ordering on the characteristics of normal and superconducting states of HTSC-oxides YBa2Cu3Ox

It is shown that, as a result of heating YBa 2 Cu 3 O x samples at temperatures in the range of 200–450°C with subsequent isothermal treatment and cooling, the correlation between concentrations of oxygen atoms and vacancies in the CuO x −6 -plane changes, and at x =6.83, 6.80, 6.75 and 6.67 ordered states arise. Ordering is distinctly seen in curves P ( x ) (the volume of superconducting phase versus x ) and σ ( x ) (conductivity at room temperature versus x ). The analysis of the correlation between these characteristics allows one to substantiate a concept of a superconducting cluster, the structure of which approaches the ordered state. The charge carrier concentration in it is not far from the value corresponding to full filling of the bands.