Mechanical and electrical driving field induced high-frequency dielectric anomalies in ferroelectric systems

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dc.contributor.authorGuerra, J. de Los S.
dc.contributor.authorEiras, J. A.
dc.contributor.institutionUniversidade Federal de São Carlos (UFSCar)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:24:47Z
dc.date.available2014-05-20T15:24:47Z
dc.date.issued2007-09-26
dc.description.abstractPolycrystalline or single-crystal ferroelectric materials present dielectric dispersion in the frequency range 100 MHz-1 GHz that has been attributed to a dispersive ( relaxation-like) mechanism as well as a resonant mechanism. Particularly in 'normal' ferroelectric materials, a dielectric response that is indistinguishable from dispersion or a resonance has been reported. Nevertheless, the reported results are not conclusive enough to distinguish each mechanism clearly. A detailed study of the dielectric dispersion phenomenon has been carried out in PbTiO3-based ferroelectric ceramics, with the composition Pb1-xLaxTiO3 (x = 0.15), over a wide range of temperatures and frequencies, including microwave frequencies. The dielectric response of La-modified lead titanate ferroelectric ceramics, in 'virgin' and poled states, has been investigated in the temperature and frequency ranges 300-450 K and 1 kHz-2 GHz, respectively. The results revealed that the frequency dependence of the dielectric anomalies, depending on the measuring direction with respect to the orientation of the macroscopic polarization, may be described as a general mechanism related to an 'over-damped' resonant process. Applying either a uniaxial stress along the measurement field direction or a poling electric field parallel and/or perpendicular to the measuring direction, a resonant response of the real and imaginary components of the dielectric constant is observed, in contrast to the dispersion behavior obtained in the absence of the stress, for the 'virgin' samples. Both results, resonance and/or dispersion, can be explained by considering a common mechanism involving a resonant response (damped and/or over-damped) which is strongly affected by a ferroelastic-ferroelectric coupling, contributing to the low-field dielectric constant.en
dc.description.affiliationUniv Fed Sao Carlos, Dept Fis, Grp Ceram Ferroeletr, BR-13565670 Sao Carlos, SP, Brazil
dc.format.extent15
dc.identifierhttp://dx.doi.org/10.1088/0953-8984/19/38/386217
dc.identifier.citationJournal of Physics-condensed Matter. Bristol: Iop Publishing Ltd, v. 19, n. 38, 15 p., 2007.
dc.identifier.doi10.1088/0953-8984/19/38/386217
dc.identifier.issn0953-8984
dc.identifier.urihttp://hdl.handle.net/11449/35334
dc.identifier.wosWOS:000249255400019
dc.language.isoeng
dc.publisherIop Publishing Ltd
dc.relation.ispartofJournal of Physics: Condensed Matter
dc.relation.ispartofjcr2.617
dc.relation.ispartofsjr0,875
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.titleMechanical and electrical driving field induced high-frequency dielectric anomalies in ferroelectric systemsen
dc.typeArtigo
dcterms.licensehttp://iopscience.iop.org/page/copyright
dcterms.rightsHolderIop Publishing Ltd

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