EXAFS of the superconducting oxide BaPb 1− xBi xO 3

Abstract

The two-valence state Bi 3+ and Bi 5+ of Bi in the semiconductor BaBiO 3 and in the BaPb 1− x Bi x O 3 ( x = 0, 0.25, 0.6 and 1) system has been determined from the EXAFS spectra above the L III-edges of Ba, Pb and Bi. Peaks in the radial distribution function up to 5 Å from the absorber have been identified through a model calculation using theoretical amplitudes and phase shifts and the interatomic distances from neutron diffraction measurements. We found indication of local disorder in the Pb-Bi sublattice for the mixed compound.