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Please use this identifier to cite or link to this item: http://acervodigital.unesp.br/handle/11449/40288
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dc.contributor.authorCastillo, J.-
dc.contributor.authorMateron, E. M.-
dc.contributor.authorCastillo, R.-
dc.contributor.authorVargas, R. A.-
dc.contributor.authorBueno, Paulo Roberto-
dc.contributor.authorVarela, José Arana-
dc.date.accessioned2014-05-20T15:31:02Z-
dc.date.accessioned2016-10-25T18:06:46Z-
dc.date.available2014-05-20T15:31:02Z-
dc.date.available2016-10-25T18:06:46Z-
dc.date.issued2009-06-01-
dc.identifierhttp://dx.doi.org/10.1007/s11581-008-0308-y-
dc.identifier.citationIonics. Heidelberg: Springer Heidelberg, v. 15, n. 3, p. 329-336, 2009.-
dc.identifier.issn0947-7047-
dc.identifier.urihttp://hdl.handle.net/11449/40288-
dc.identifier.urihttp://acervodigital.unesp.br/handle/11449/40288-
dc.description.abstractWe report on electrical relaxation measurements of (1-x)NH4H2PO4-xTiO(2) (x = 0.1) composites by admittance spectroscopy, in the 40-Hz-5-MHz frequency range and at temperatures between 303 and 563 K. Simultaneous thermal and electrical measurements on the composites identify a stable crystalline phase between 373 and 463 K. The real part of the conductivity, sigma', shows a power-law frequency dependence below 523 K, which is well described by Jonscher's expression sigma' = sigma(0)(1 + (omega/omega(p))(n)), where sigma(0) is the dc conductivity, omega(p)/2 pi = f(p) is a characteristic relaxation frequency, and n is a fractional exponent between 0 and 1. Both sigma(0) and f(p) are thermally activated with nearly the same activation energy in the II region, indicating that the dispersive conductivity originates from the migration of protons. However, activation energies decrease from 0.55 to 0.35 eV and n increases toward 1.0, as the concentration of TiO2 nanoparticles increases, thus, enhancing cooperative correlation among moving ions. The highest dc conductivity is obtained for the composite x = 0.05 concentration, with values above room temperature about three orders of magnitude higher than that of crystalline NH4H2PO4 (ADP), reaching values on the order of 0.1 (Omega cm)(-1) above 543 K.en
dc.description.sponsorshipInternational Science Program of Uppsala University, Sweden-
dc.description.sponsorshipColombian Science Foundation-
dc.description.sponsorshipCOL-CIENCIAS-
dc.format.extent329-336-
dc.language.isoeng-
dc.publisherSpringer Heidelberg-
dc.sourceWeb of Science-
dc.subjectProtonic compositesen
dc.subjectPhase behavioren
dc.subjectElectrical relaxationen
dc.titleElectrical relaxation in proton conductor composites based on (NH4)H2PO4/TiO2en
dc.typeoutro-
dc.contributor.institutionUniv Quindio-
dc.contributor.institutionUniv Valle-
dc.contributor.institutionUniversidade Estadual Paulista (UNESP)-
dc.description.affiliationUniv Quindio, Programa Fis, Armenia, Armenia-
dc.description.affiliationUniv Valle, Dept Fis, Cali 25360, Colombia-
dc.description.affiliationUniv Estadual Paulista, Dept Quim Fis, Inst Quim, BR-14800900 São Paulo, Brazil-
dc.description.affiliationUnespUniv Estadual Paulista, Dept Quim Fis, Inst Quim, BR-14800900 São Paulo, Brazil-
dc.identifier.doi10.1007/s11581-008-0308-y-
dc.identifier.wosWOS:000266477300007-
dc.rights.accessRightsAcesso restrito-
dc.relation.ispartofIonics-
Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

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