Simultaneous reverse Monte Carlo refinements of local structures in perovskite solid solutions using EXAFS and the total scattering pair-distribution function

Reverse Monte Carlo (RMC) refinements using a combined real-space fit of the neutron/X-ray total scattering pair-distribution function (PDF) and the extended X-ray absorption fine structure (EXAFS) were developed and implemented as an extension to the public domain computer software RMCProfile. The effectiveness of combined PDF/EXAFS RMC refinements was tested using perovskite Ca(Zr,Ti)O₃ solid solutions. The analyses revealed that combining two types of data yields correct distributions of the Ti-O and Zr-O distances that could not be recovered using either of the techniques alone because of the substantial overlap between the Ti-O and Zr-O partial PDFs. The combined refinements enabled reasonably accurate reproduction of most of the local structure characteristics, including the dependence of Ca displacements on the local B-cation coordination around Ca.