NMR and β-NMR Studies of Diffusion in Interface-Dominated and Disordered Solids

NMR and impedance studies of nanocrystalline and amorphous ion conductors: lithium niobate as a model system

“…6 Similar results were obtained for the nanocrystalline anionic conductor CaF 2 . 22,42 The NMR results confirm, that this nanocrystalline LiNbO 3 sample is characterized by a heterogeneous, i. e., two-component structure of crystalline grains and amorphous grain boundaries.…”

“…which represents the low-temperature flank of the characteristic -peak 22 , the background ) ( 1 activation energy of about 0.27 eV was found by means of 7 Li NMR relaxation. 27 Such small differences in activation energies are expected since both materials are prepared by slightly different preparation routes (cf.…”

“…6,21,22,27 Contrary to the amorphous and microcrystalline material, the central line of the 16 h high-energy ball-milled sample shows two contributions at the same frequency when a temperature of about 330 K is attained. The narrow contribution, which can be described with a Lorentzian shape, is attributed to the fast subset of Li ions located in the structurally disordered interfacial regions.…”

“…Solid-state nuclear magnetic resonance (NMR) techniques 21,22 in combination with impedance spectroscopy measurements 5,23 were used to probe microscopic as well as macroscopic Li diffusion parameters of LiNbO 3 . In its single crystalline form, lithium niobate is a poor Li conductor with a very small Li diffusion coefficient.…”

Local electronic structure inMgB2fromB12Indris1, Heitjans2, Hattendorf3 et al. 2007Phys. Rev. BSelf Cite

“…16,17 The polarization of the 12 B nuclei can be destroyed by application of a radiofrequency ͑rf͒ field with an appropriate frequency. ␤-NMR spectra consist of the asymmetry A ␤ recorded as a function of the rf .…”