Evidences of Superconductivity without Direct Relation to Valence   Electron Density in Metal Doped Y123 Cuprates
  We investigated systemically YBa2Cu3-x(Fe, Co, Al, Zn)xO7-{\delta} (x=0.0\sim0.5) cuprates through the XRD, the test of superconductivity, oxygen contents,positron annihilation technology and simulated calculations. The experimental results and theoretic calculations support such a conclusion that the Tc does not depend directly on the density of valence electron in the samples. Moreover, whether or not it may imply some correlations between Fe-oxide superconductors and cuprates that Fe doped Y123 samples show some unique characteristics. 
Xiao-Xia Wang, Guo-Ru Yu, Jiang-Hui Li, Ping-Lin Li
cond-mat.supr-con