Hole states in Eu0.9-xPrxCa0.1BaSrCu3O7-delta studied by X-ray absorption spectroscopy
Journal
Journal of the Chemical Society-Dalton Transactions
Journal Issue
12
Pages
2065-2069
Date Issued
1999
Author(s)
Abstract
The hole states located on different oxygen sites have been investigated in Eu0.9-xPrxCa0.1BaSrCu3O 7-δ with increasing Pr3+ substitution by high-resolution oxygen K-edge and copper L-edge X-ray absorption spectra. The results reveal that the hole states are depleted systematically by the substitution and in turn lead to a reduction in Tc. However, the rate at which the depletion occurs is lower in Eu0.9-xPrxCa0.1BaSrCu3O 7-δ compared to that in Y1-xPrxBa2Cu3O7-δ and Dy1-xPrxBa2Cu3O7-δ. This is due to the partial substitution of Ba2+ by Sr2+ ions and R (rare earth element) by Ca2+ ions in the present case. The depletion of hole states gives evidence in support of the hole-depletion models based on Pr4f-O 2pπ hybridization. The possible reasons for the anomalous behavior of Pr3+ ions in RBa2Cu3O7-δ are also discussed.
Type
journal article