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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 article, structural characterization of all the samples was carried out by the x-ray diffraction technique, and the room temperature dielectric properties, namely relative permittivity and ac conductivity, were studied as a function of applied frequency in the range from 20-Hz to 1-MHz.
Abstract: Co1.2−xMnxFe1.8O4 (0≤x≤0.4) compositions were synthesized by the autocombustion route by keeping the oxidizer to fuel ratio (Φe) at 1. Thermogravimetric analysis (TGA) shows the stable phase formation takes place at a temperature above 600 °C. Structural characterization of all the samples was carried out by the x-ray diffraction technique. Room temperature magnetization measurements showed that, for the substitution of Co by Mn, there is an initial increase in the saturation magnetization (Ms) for lower concentrations (i.e. x = 0.1 and 0.2); and then the magnetization decreases for higher concentrations (i.e. x = 0.3 and 0.4). Also, it is observed that the coercivity (Hc) goes on decreasing with the substitution of Mn content, except for x = 0.3 which shows a slight increase in coercivity as compared to x = 0.4. Room temperature dielectric properties, namely relative dielectric permittivity (e'), dielectric loss (tanδ) and ac conductivity (σac), for all the samples were studied as a function of applied frequency in the range from 20 Hz to 1 MHz. These studies indicate that the relative dielectric permittivity goes on increasing with the increase of Mn content in Co ferrite and also all the samples show the usual dielectric dispersion which is due to the Maxwell–Wagner-type interfacial polarization. The ac conductivity measurement suggests that the conduction is due to small polaron hopping.
107 citations
TL;DR: The piezoelectric effect in wood, i.e. the occurrence of electric polarization under mechanical stress and also of mechanical strain in an electric field, was explained by considering the uniaxial orientation of cellulose crystallites in fibers and their monoclinic symmetry as discussed by the authors.
Abstract: The piezoelectric effect in wood, i.e. the occurrence of electric polarization under mechanical stress and also of mechanical strain in an electric field, was accounted for by considering the uniaxial orientation of cellulose crystallites in fibers and their monoclinic symmetry. A shear stress in one plane, including the grain direction, produced electrical polarization perpendicular to it. The value of the piezoelectric modulus for wood was approximately one twentieth of that of a quartz crystal. The chemical treatments which transform the lattice structure from cellulose I to II or III, increased the piezoelectric modulus. However, gamma-ray irradiation up to a dose sufficiently high to decrease the molecular weight had only little influence on the piezoelectric modulus. The variation with temperature of the phase angle between sinusoidal stress and polarization showed a maximum of advanced phase around room temperature and a maximum of delayed phase at about-100°C. Dielectric and viscoelastic measurements indicated that the former was caused by the dielectric loss due to water at a temperature above freezing and the latter by the viscoelastic loss due to local vibrations of cellulose molecules. The piezoelectric polarization in wood can be utilized in technical problems such as the measurement of shock velocity in timber. The physiological meaning of the piezoelectrical effect in plants has not been investigated.
107 citations
01 Dec 1952
TL;DR: In this article, the properties of TEM-mode propagation for a wire or a strip of finite width immersed in a uniform infinite dielectric above a ground plane are examined.
Abstract: Properties of TEM-mode propagation are examined for a wire or a strip of finite width immersed in a uniform infinite dielectric above a ground plane. Characteristic impedance, power flow, and conductor and dielectric losses are considered. The discussion of the TEM mode is in the complex plane.
106 citations
TL;DR: The realism of single phase cubic spinel creation of the synthesized ferrite samples was studied by the DTA-TGA, XRD, SEM, EDX, FT-IR, VSM and dielectric measurements.
106 citations
TL;DR: In this article, the effect of GNP incorporation on electromagnetic properties and electromagnetic interference shielding effectiveness (SE) of PLA and PBAT was investigated and the applicability of Sihvola's mixing rule of complex electrical permittivity to these nanocomposites was studied.
106 citations