X-ray absorption near-edge structure of Pr1-xBa2+xCu3O7

PrBa2Cu3O7 (Pr123) has attracted much attention due to its non-superconduct ivity and other anomalies. The very recent reports on superconducting Pr123 , instead of putting an end on this issue, virtually stimulate more controv ersies. One of the proposed explanations for the recently observed supercon ductivity in Pr123 is that the samples could be Ba-rich Pr123. To investiga te this possibility, we have prepared Pr1-xBa2+xCu3O7 With x=0 to 0.3. It i s found that resistivity of the samples becomes smaller with increasing x, together with elongation of the c-axis. O K-edge x-ray absorption structure indicates an increase in the carrier concentration with Ba doping. However , carriers are introduced in a peculiar way rather than simply added into C uO2 planes.