X-ray spectroscopic study of the electronic structure of Y$_{1-x}$Pr$_x$Ba$_2$Cu$_3$O$_7$
H. Yamaoka, H. Oohashi, I. Jarrige, T. Terashima, Y. Zou, H. Mizota, S. Sakakura, T. Tochio, Y. Ito, E. Ya Sherman, and A. Kotani

We present a detailed investigation of the bulk electronic properties of Y$_{1-x}$Pr$_x$Ba$_2$Cu$_3$O$_7$ (YPrBCO) using x-ray absorption spectroscopy in the partial fluorescence yield mode (PFY-XAS) at Pr $L_{3}$, Ba $L_{3}$ and Cu $K$-edges together with Pr-$2p_{3/2}3d_{5/2}$ and Cu-$1s2p$ resonant inelastic x-ray scattering (RIXS). Pr-$L_{3}$ PFY-XAS spectra show that Pr is in the mixed-valence state (with the valence number slightly greater than 3) for the whole $x=$0.2$\sim$1 range, while the Pr valence decreases with increasing $x$. The decrease of the Pr$^{4+}$ component upon Pr doping, hinting at a weakening Pr-O hybridization, is inconsistent with the scenario according to which the increase in Pr-O hybridization quenches the superconductivity in YPrBCO for $x\geq0.6$. It rather suggests that the superconductivity may be suppressed by the total increase of the Pr-related states in the electronic structure due to the Pr ion concentration upon doping. No doping dependence is found in the electronic structure of the Ba and Cu sites, consistent with their invariant environment. No temperature dependence in our data is observed within the experimental accuracy.

© 2008 The American Physical Society.