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. 7Li 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 (T1) measured by saturation recovery and longitudinal relaxation times in the rotating frame (T1ρ) measured using the pulse sequence (π/2-spin lock τ acquisition) with lock radio-frequency field υ = 62.5 kHz and the T2 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 T1 and T1ρ show two different types of lithium cations with fast and slow dynamics.