Cu K-Edge Study of (Tl0.5Pb0.5)Sr2Ca1-xYxCu2O7-δ

Abstract

Near-edge x-ray-absorption spectra at the Cu K-edge has been measured for (Tl0.5Pb0.5)Sr2Ca 1-x Y x Cu2O 7-δ compound series. It is found that both the intensity of the quadruple 1s → 3d transition feature and the edge-energy decrease with increasing x. Our results show that the Cu valence decreases slightly with the substitution of Ca +2 by Y +3. This result, together with recent O K-edge result the O -2p holes are reduced by the substitution, indicates that electronic charge is transferred into the entire CuO 2 layers by the Y +3 for Ca +2 substitution.