Author/Authors :
Chen، نويسنده , , J.M. and Nachimuthu، نويسنده , , P. and Lin، نويسنده , , J.Y. and Hong، نويسنده , , I.P. and Chang، نويسنده , , C.F. and Yang، نويسنده , , H.D.، نويسنده ,
Abstract :
O K-edge X-ray absorption near-edge structure (XANES) spectroscopy of (R0.8Pr0.2)Ba2Cu3O7 (R=Y, Tm, Dy, Gd, Eu and Sm) has been performed to investigate the dependence of hole distribution on ionic size of the R3+ ions. Near the O 1s absorption edge, pre-peaks at ∼527.8 and ∼528.5 eV are assigned to transitions into O 2p hole states located in the CuO3 ribbons and CuO2 planes, respectively. As deduced from O K-edge X-ray absorption spectra, the hole concentrations in the CuO2 planes decrease monotonically with increasing ionic size of the rare-earth elements. The present XANES results clearly demonstrate that the suppression of superconductivity in (R1−xPrx)Ba2Cu3O7 with ionic radius of the R3+ ions results predominantly from the hole-depletion effect.
