Topic
Dielectric loss
About: Dielectric loss is a research topic. Over the lifetime, 20296 publications have been published within this topic receiving 349254 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the authors proposed and demonstrated that substantially enhanced discharge efficiency of PVDF-based polymers nanocomposites could be achieved by simultaneously optimizing their topological-structure and phase composition.
111 citations
TL;DR: Capacitance and dissipation factor values of polymethyl methacrylate-co-poly 4vinyl pyridine N -oxide (PMMA-CO-P4VPNO) were measured in the frequency range 0.01-100 kHz and temperature range 300-410 K as discussed by the authors.
111 citations
TL;DR: The improved microwave absorption properties are a consequence of a proper electromagnetic match and the enhanced magnetic loss besides its dielectric loss due to the existence of the core/shell structure in CoFe(2)O(4) composites.
Abstract: CoFe2O4 nanoparticles were fabricated by a sol–gel method and then were coated with Co3Fe7–Co by means of a simple reduction process at different temperatures under 2% H2 with the protection of argon to generate the dielectric-core/metallic-shell structure. The optimum reflection loss (RL) calculated from permittivity and permeability of the 80 wt% CoFe2O4/Co3Fe7–Co and 20 wt% epoxy resin composites reached − 34.4 dB, which was much lower than that of unreduced CoFe2O4 and epoxy resin composites, at 2.4 GHz with a matching thickness of 4.0 mm. Moreover the RL exceeding − 10 dB in the maximum frequency range of 2.2–16 GHz was achieved for a thickness of composites of 1.0–4.5 mm with 600 °C thermal reduction process. The improved microwave absorption properties are a consequence of a proper electromagnetic match and the enhanced magnetic loss besides its dielectric loss due to the existence of the core/shell structure in CoFe2O4 composites. Thus, the reductive CoFe2O4 nanoparticles have great potential for being a highly efficient microwave absorber.
111 citations
TL;DR: In this article, a simple one-step hydrothermal method without using any toxic solvents was used to prepare pure MnO2 nanorods and reduced graphene oxide (RGO) nanocomposites for microwave absorption.
Abstract: Pure MnO2 nanorods and MnO2 nanorod/reduced graphene oxide (RGO) nanocomposites are prepared for microwave absorption by using a simple one-step hydrothermal method without using any toxic solvents. The results demonstrate that the MnO2 phases possess a high crystallization degree in both the pure nanorods and the nanocomposites but the nanocomposites exhibit two hybrid Mn phases, distinct from MnO2 in the pure nanorods. The electromagnetic characteristics and electromagnetic wave (EMW) absorption properties of the materials are investigated. The thickness dependent reflection loss shows that the peak frequency and effective absorption bandwidth all decrease with the increasing material thickness. Compared with the pure MnO2 nanorods, the introduction of RGO enhances the microwave absorbing intensity and effective absorption bandwidth. The maximum reflection loss value of the nanocomposites reaches −37 dB at 16.8 GHz with a thickness of 2.0 mm and the wide bandwidth corresponding to the reflection loss below −10 dB starts from 13 GHz until a value of −22 dB at 18 GHz. The enhanced microwave absorbing properties can be ascribed to the improved permittivity, dielectric loss and especially the synergistic effects between MnO2 nanorods and RGO nanosheets at their interfaces in the unique nanostructures of the MnO2/RGO nanocomposites.
111 citations
TL;DR: In this article, an In + Ta co-doped TiO2 material system with high dielectric permittivity and low temperature dependent loss was reported. But the defect analysis was performed in the presence of electron-pinned defect dipoles (EPDDs).
Abstract: Colossal permittivity (CP) materials have many important applications in electronics but their development has generally been hindered due to the difficulty in achieving a relatively low dielectric loss. In this work, we report an In + Ta co-doped TiO2 material system that manifests high dielectric permittivity and low dielectric loss based on the electron-pinned defect-dipole design. The dielectric loss can be reduced down to e.g. 0.002 at 1 kHz, giving high performance, low temperature dependent dielectric properties i.e. er > 104 with tanδ < 0.02 in a broad temperature range of 50–400 K. Density functional theory calculations coupled with the defect analysis uncover that electron-pinned defect dipoles (EPDDs), in the form of highly stable triangle-diamond and/or triangle-linear dopant defect clusters with well-defined relative positions for Ti reduction, are also present in the host material for the CP observed. Such a high-performance dielectric material would thus help for practical applications and points to further discovery of promising new materials of this type.
111 citations