NMR and conductivity study of the protonic conductor HPb2Nb3O10 center dot nH(2)O
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Elsevier B.V.
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Resumo
Electrical conductivity and H-1 Nuclear Magnetic Resonance (NMR) techniques were used to investigate the ion-exchanged layered lead-niobate perovskite HPb2Nb3O10. nH(2)O, over the temperature range 90-350 K. Compounds were synthesized by the sol-gel method and calcinated at 650 degreesC. Analysis of the NMR data gives activation energies for the proton motion in the range 0.14-0.40 eV, which are dependent on the water content. The frequency and temperature dependencies of the proton spin-lattice relaxation times show that the character of the motion of the: water molecules is essentially two-dimensional, reflecting the layered structure of the material. The H-1 line-narrowing transition and the single spin-lattice relaxation rate maximum, observed in the hydrated compounds, are consistent with a Grotthuss-like mechanism for the proton diffusion. (C) 2000 Elsevier B.V. B.V. All rights reserved.
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NMR, impedance spectroscopy, proton conductor, sol-gel, perovskite
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Inglês
Citação
Solid State Ionics. Amsterdam: Elsevier B.V., v. 136, p. 243-247, 2000.
