Topic
Dielectric loss
About: Dielectric loss is a research topic. Over the lifetime, 20296 publications have been published within this topic receiving 349254 citations.
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TL;DR: In this paper, the effect of acceptor doping on the dielectric and piezoelectric properties of MnO2-based polycrystalline materials was investigated.
Abstract: The effect of MnO2 addition on the dielectric and piezoelectric properties of 0.4Pb(Mg1∕3Nb2∕3)O3–0.25PbZrO3–0.35PbTiO3 single crystals was investigated. Analogous to acceptor doping in “hard” Pb(Zr,Ti)O3 based polycrystalline materials, the Mn doped crystals exhibited enhanced mechanical Q (∼1050) with low dielectric loss (∼0.2%), while maintaining ultrahigh electromechanical coupling k33>90%, inherent in domain engineered single crystals. The effect of acceptor doping was also evident in the build-up of an internal bias (Ei∼1.6kV∕cm), shown by a horizontal offset in the polarization-field behavior. Together with the relatively high usage temperature (TR-T∼140°C), the Mn doped crystals are promising candidates for high power and broad bandwidth transducers.
132 citations
TL;DR: In this paper, the piezoelectric, dielectric and ferroelectric properties of porous PZT ceramics were investigated as a function of pore shape and porosity.
Abstract: Porous lead zirconate titanate (PZT 95/5) ferroelectric ceramics were prepared by sintering compacts consisting of PZT and pore formers. The piezoelectric, dielectric and ferroelectric properties of porous PZT ceramics were investigated as a function of pore shape and porosity. Piezoelectric coefficient ( d 33 ), dielectric constant ( ɛ 33 ) and remnant polarization ( P r ) decreased with an increase in porosity, and the porous PZT ceramics with spherical pores exhibited better properties than that with irregular pores. Furthermore, the electrical conductivities of PZT ceramics were investigated to explain the phenomena that porous PZT ceramics exhibited lower dielectric loss (tan δ ) than dense PZT ceramics in the temperature range from 250 to 500 °C.
131 citations
TL;DR: In this paper, a dielectric layer (NH2-MWNT/PI composites) is intercalated between the two insulating layers (pure PI, acting as both the bottom and the top layers).
Abstract: Novel amino-modified-CNT/polyimide (NH2-MWNT/PI) flexile composite films with a sandwich structure were prepared through step-by-step casting, in which a dielectric layer (NH2-MWNT/PI composites) intercalated between the two insulating layers (pure PI, acting as both the bottom and the top layers). Due to the high capacitance of the dielectric layer and the effective blocking off conductive paths by the insulating layers, the sandwich composite films show a high dielectric constant and ultralow dielectric loss, and the dielectric constants of the composite films are almost frequency independent between 1 and 1000 kHz. It is notable that the NH2-MWNT/PI ratio of the mid-layer markedly influences the dielectric property of the composite film. When the NH2-MWNT content of the mid-layer is 10 wt%, the multi-layer composite film (P-10-P) shows the highest dielectric constant (e′) of 31.3 at 1 kHz, while the dielectric loss (tan δ) of the P-10-P is only 0.0016. Furthermore, the obtained multi-layer composite films have high breakdown strength and maximum energy storage density. The mechanical properties and thermal properties of the composite films were also examined in this work.
131 citations
TL;DR: Data indicate that significant reduction in leakage currents and dielectric losses and improvement in dielectrics breakdown strengths resulted when electropositive phenyl, electron-withdrawing functional groups were located at the polymer-particle interface.
Abstract: The interface between the polymer and the particle has a critical role in altering the properties of a composite dielectric Polymer-ceramic nanocomposites are promising dielectric materials for many electronic and power devices, combining the high dielectric constant of ceramic particles with the high dielectric breakdown strength of a polymer Self-assembled monolayers of electron rich or electron poor organophosphate coupling groups were applied to affect the filler–polymer interface and investigate the role of this interface on composite behavior The interface has potential to influence dielectric properties, in particular the leakage and breakdown resistance The composite films synthesized from the modified filler particles dispersed into an epoxy polymer matrix were analyzed by dielectric spectroscopy, breakdown strength, and leakage current measurements The data indicate that significant reduction in leakage currents and dielectric losses and improvement in dielectric breakdown strengths resulte
131 citations
TL;DR: In this article, the complex (electric) permittivity of aqueous solutions of d-glucose and d-fructose has been determined as a function of frequency υ between 300 kHz and 40 GHz.
Abstract: At some solute concentrations c between 1 and 5.4 mol/L, the complex (electric) permittivity of aqueous solutions of d-glucose and d-fructose has been determined as a function of frequency υ between 300 kHz and 40 GHz. The permittivity spectrum of the 5.4 mol/L d-fructose solution has been measured at six temperatures between 10 and 35 °C, and the other spectra have been taken at 25 °C. All dielectric spectra revealed one dispersion/dielectric loss region, which indicated a rather homogeneous relaxation of the solute and solvent dipole moments. Analytically, the measured spectra were represented by the Cole−Cole relaxation spectral function, which corresponds with a continuous, symmetrically bell shaped relaxation time distribution. The parameters of the spectral function are discussed to show that the monosaccharides exhibit unusual hydration properties. Particularly, when treated in terms of a wait-and-switch model of dipole reorientation, the principal dielectric relaxation time is indicative of the ex...
131 citations