Lone Pair Ordering in Mixed Valence Oxide Perovskites and Superconductors

Abstract

This dissertation describes investigations of BaBiO3 and of its lead-doped counterparts, aiming to elucidate the relationship between charge disproportionation and structural change. To characterize the long-range average structures of these materials with varying temperatures, powder neutron diffraction data collected using the time-of-flights diffractometers NOMAD and POWGEN was analysed using the Rietveld method. These analyses were followed by neutron total scattering analysis from data measured on the same instruments, to obtain short-range local structural information, using pair distribution function methods.