THE PLANE BUCKLING ANOMALIES AND SUPERCONDUCTIVITY OF COPPER OXIDE MATERIALS. A.V. Klochkov, O.A. Usov, Ioffe Physico-Technical Institute, Polytechnical str., 26, 194021 St.Petersburg, Russia

The interplay between the copper oxide plane buckling parameters and superconducting properties of cuprate high-temperature superconductors (HTSC) and related materials including Pr anomalies are discussed. The structure parameters are determined by X-ray diffraction data analysis and were shown to correlate with free hole carrier concentrations and critical temperature of superconductors. From consideration of local structure of copper oxide layers all cuprate HTSC compounds are found to be separated for two different types:buckled SC plane (BSP) like Y123, Bi2212 etc and flat plane (FSP) like 1201, 214(T') etc. For FSP type compounds the critical temperature has optimal value for flat copper layers and Pr anomalies were not observed. If buckling increases the critical temperature of FSP compounds decreases. For BSP one it increases, the Pr anomaly being observed. From analysis of structure parameters of R123 compounds (R - rare earth elements) we found that buckling of CuO layers increase but BaO decrease on ionic radius and for Pr they should be equal. But the buckling of CuO layers are found to abrupt to value known for insulators. Thus for Pr123 the layers assumed to be unstable due to large ionic radius of Pr and redistribution of charges between the layers. The analysis of buckling anomalies and its influence on the electronic properties are supposed to be important step for discovering of physical factors responsible for high critical temperatures.