Study of oxygen-nitrogen replacement in BaTiO3 by 14N solid-state nuclear magnetic resonance

We here report about oxygen-nitrogen substitution in the anionic sublattice of BaTiO3 by calcination in a NH3 flow at 950 degrees C. The resulting oxynitride BaTi(O,N)(3) is shown to possess cubic structure by powder XRD and to contain 0.57 mass percent of nitrogen by hot gas extraction analysis. Solid-state N-14-NMR is used to characterize the electronic surroundings of the N3- anions in the oxynitride. Analysis of N-14-NMR line shapes as well as comparison of line positions to those of TiN and BaTaO2N implies that the incorporated nitrogen anions do indeed occupy the oxygen sites in the BaTi(O,N)3 lattice. The study illustrates the usefulness of solid-state NMR as a method for tracking ion substitution in highly symmetric environments, such as perovskite-structured oxynitrides, because of its high sensitivity to symmetry changes in the local electronic surroundings of nuclei.