Solid-state NMR study of the anionic conductor Ca-doped Y(2)Ti(2)O(7)

Doping the pyrochlore (Y(2)Ti(2)O(7)) with the Ca(2+) has been reported to improve the oxygen ionic conductivity. (17)O and (89)Y solid-state NMR has been used in work reported here to probe the local environment of the oxygen and yttrium sites in these materials. Although the conductivity of these materials is only moderate, variable-temperature, one-dimensional (17)O NMR experiments and two-dimensional (17)O magnetization exchange spectroscopy show that oxygen-ion jumps occur between the oxygen sites nearby titanium. Motion at ambient temperatures involves the O1 and local environments created by the Ca(2+) doping; motion does not involve the O2 oxygen site coordinated to four yttrium ions.