Energy shift and hole localization in Y1-xPrxBa2Cu3O7-delta from the O 1s X-ray near-edge-absorption spectroscopy

High-resolution O 1s x-ray near-edge-absorption spectra of Y1-xPrxBa2Cu3O7- delta (abbreviated as Pr-x-123) have been measured. The spectra indicate th at the Pr ions not only affect the spectral energies but also the spectral profiles; The binding energy of the 1s state of the oxygen in the CuO2 plan es is suggested to become smaller when Y is substituted by Pr. The number o f holes derived from the spectral intensity designated the transition of O 1s to the valence band suggests that the fraction of Pr4+ is about 0.3. The holes residing in Pr-x-123 are demonstrated to be localized and completed when Pr concentration is increased beyond x congruent to 0.5. The result of hole localization is consistent with a model based on the Pr 4f - O 2p hyb ridization.