Preferential Substitution of Barium in Orthorhombic Lead Metaniobate

Abstract

The crystal structure of a ferroelectric lead metaniobate containing 10 mole% barium was refined using the Rietveld method on diffraction patterns obtained using multiple diffraction techniques. Cu Kα X-ray diffraction, synchrotron diffraction, and neutron diffraction were used to provide complementary information on the structure of this substitutionally-alloyed compound. Neutron diffraction was used as a starting point for refinement with the X-ray diffraction methods used for final structural refinements. Barium was found to preferentially substitute on lead sites in the lead metaniobate crystal structure.

Acknowledgments

This research and researchers have been supported by the U.S. National Science Foundation under awards DMR-0224991 and DMR-0805022 and the Indiana 21st Century Research and Technology Fund No. 092200-0076. This work has benefited from the use of the Los Alamos Neutron Science Center at the Los Alamos National Laboratory, funded by the U.S. Department of Energy under Contract W-7405-ENG-36 and the NSLS at Brookhaven National Laboratory, supported by the U.S. Department of Energy, Division of Materials Sciences and Division of Chemical Sciences, under Contract No. DE-AC02 98CH10886. The authors express their gratitude to Sven Vogel and Darrick Williams at the Los Alamos Neutron Science Center and Steve Ehrlich at the National Synchrotron Light Source.