Dielectric loss

About: Dielectric loss is a research topic. Over the lifetime, 20296 publications have been published within this topic receiving 349254 citations.

Oxygen-vacancy-related high-temperature dielectric relaxation in SrTiO3 ceramics

Abstract: Quantum paraelectric SrTiO3 has resulted in many investigations because of the anomalous properties. Here, using the conventional solid-state reaction method, we fabricated polycrystalline SrTiO3 ceramics with pure cubic perovskite structure. A dielectric loss peak is observed at around 450 K and 100 Hz and it shifts to higher temperature with increasing frequency. The typical high-temperature dielectric relaxation process is confirmed to be related to the oxygen vacancies (OVs) inside ceramics. More interestingly, a Cole–Cole fitting to loss peaks reveals a weaker correlation among OVs for such dielectric materials compared with that of ferroelectrics.

Novel Low‐Firing Microwave Dielectric Ceramic LiCa3MgV3O12 with Low Dielectric Loss

Abstract: Novel low temperature firing microwave dielectric ceramic LiCa3MgV3O12 (LCMV) with garnet structure was fabricated by the conventional solid-state reaction method. The phase purity, microstructure, and microwave dielectric properties were investigated. The densification temperature for the LCMV ceramic is 900°C. LCMV ceramic possessed er = 10.5, Qu × f = 74 700 GHz, and τf = −61 ppm/°C. Furthermore, 0.90LiCa3MgV3O12–0.10CaTiO3 ceramic sintered at 925°C for 4 h exhibited good properties of er = 12.4, Qu × f = 57 600 GHz, and τf = 2.7 ppm/°C. The LCMV ceramic could be compatible with Ag electrode, which makes it a promising ceramic for LTCC technology application.

Fluorinated amorphous carbon thin films grown by helicon plasma enhanced chemical vapor deposition for low dielectric constant interlayer dielectrics

Abstract: Fluorinated amorphous carbon thin films (a‐C:F) for interlayer dielectrics are grown by helicon plasma enhanced chemical vapor deposition. The source gases are CH4, CF4, C2F 6 and their H2mixtures. a‐C:F films can be fabricated without adding hydrogen using the helicon reactor, while in the previously reported parallel‐plate reactor, no film grows unless a hydrogen source is added. The films grown in the helicon reactor have no hydrogen content. The growth rate of the films reaches 0.3 μm/min (C2F 6) and 0.15 μm/min (CF4). The thickness of the films deposited with C2F6 does not decrease on heating to 300 °C, while the films with CF4 shrink. The dielectric constants of the films deposited from C2F6 and CF4 are 2.4 and 2.3 respectively at 1 MHz. The dielectric loss tangent of these films is 0.01 at 1 MHz.

Effect of mode-stirrer configurations on dielectric heating performance in multimode microwave applicators

Abstract: In this paper, several mode-stirrer configurations are compared in order to establish their influence on the electric-field uniformity within an irradiated dielectric sample inserted in a microwave-heating applicator. Two different scenarios are evaluated with metallic sheets moving inside the multimode applicator. The different stirrer configurations are tested and compared for low-, medium-, and high-loss dielectric sample materials. Additionally, a straightforward procedure based on a generalized plane-wave approach is proposed and evaluated as a computationally efficient alternative for calculating the electric-field distribution inside materials processed in these microwave applicators with mode stirrers. Although very different electric patterns are achieved depending on stirrer geometry and sample permittivity, the plane-wave approach has been shown to provide a very good approximation for medium and high lossy dielectric materials.