ORIGIN OF SUPERCONDUCTIVITY SUPPRESSION IN (DY1-XPRX)BA2CU3O7 STUDIEDBY SOFT-X-RAY ABSORPTION-SPECTROSCOPY

O K-edge and Cu L-23-edge x-ray-absorption near-edge structure (XANES) spectra for the series of (Dy1-xPrx)Ba2CU3O7-delta compounds (x = 0 - 0.7) were measured to investigate how the variation of hole states re lated to the superconductivity. Near the O 1s edge, prepeaks at simila r to 527.6 and similar to 528.4 eV are assigned to transitions into O 2p holes located in the CuO3 ribbons and CuO2 planes, respectively. Bo th the O 2p hole concentration in the CuO2 planes and CuO3 ribbons dec rease monotonically with increasing Pr doping, giving evidence in supp ort of the hole depletion model proposed by Liechtenstein and Mazin. I t clearly demonstrates that the suppression of superconductivity with Pr-doping results predominantly from the hole depletion effect. In the Cu 2p absorption edge, the high-energy shoulders originating from Cu 3d(9)L defected states show a linear decrease in spectral weight as th e Pr doping increases, where L denotes the ligand O 2p hole on the CuO 3 ribbons and the CuO2 planes.