7Li NMR analysis on perovskite structured Li0.15La0.28TaO3

The nanocrystalline perovskite material Li0.15La0.28TaO3 has been synthesized by alkoxide-free Pechini type sol gel method. Li-7 NMR measurements were carried out using a Bruker Avance 300 spectrometer at 116 MHz over the temperature range 150 to 400 K. Longitudinal spin-lattice relaxation times (T-1) measured by saturation recovery and longitudinal relaxation times in the rotating frame (T-1 rho) measured using the pulse sequence (pi/2-spin lock tau acquisition) with lock radio-frequency field upsilon=62.5 kHz and the T-2 relaxation time measured by Hahn echo are presented. The static Hahn-echo spectra show two different lithium sites in this perovskite oxide. Further, the relaxation measurements T-1 and T-1 rho show two different types of lithium cations with fast and slow dynamics. (c) 2006 Elsevier B.V. All rights reserved.