| Abstract: | This paper reports that the YBaYBCO, simulated calculations,
positron annihilation, cluster effectProject supported by the National
Natural Science Foundation of China (Grant No 10647145) and The
Basic Science Foundation of Henan Educational Bureau of China.7410, 7165, 3120C, 3640BThis paper reports that the YBaYBCO, simulated calculations,
positron annihilation, cluster effectProject supported by the National
Natural Science Foundation of China (Grant No 10647145) and The
Basic Science Foundation of Henan Educational Bureau of China.7410, 7165, 3120C, 3640BThis paper reports that the YBaYBCO, simulated calculations,
positron annihilation, cluster effectProject supported by the National
Natural Science Foundation of China (Grant No 10647145) and The
Basic Science Foundation of Henan Educational Bureau of China.7410, 7165, 3120C, 3640BThis paper reports that the YBa$_{2}$Cu$_{3 - x}$Zn$_{x}$O$_{7 -
\delta }\ (x=0-0.4$) samples are researched by means of x-ray
diffraction, calculations of binding energy, the positron
experiments and variations of oxygen content. The results of
simulated calculations, positron experiments and variations of
oxygen content support the existence of cluster effect. Moreover, it
is concluded that the cluster effect is an important factor on
suppression of high-$T_{\rm c}$ cuprate superconductivity and the
$T_{\rm c}$ does not depend on the density of valence electron
directly. |
