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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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Journal ArticleDOI
TL;DR: In this paper, the dielectric properties of perovskite oxides like calcium copper titanate or lanthanum doped barium titanate were investigated and it was shown that when processed in a particular way, this later material present at ambient temperature and at f ǫ = 1 Ã 1 kHz unusual interesting dielectrics properties, a so called “colossal” permittivity value up to several 106 with relatively low Dielectric losses.
Abstract: In pursuit of high permittivity materials for electronic application, there has been a considerable interest recently in the dielectric properties of various perovskite oxides like calcium copper titanate or lanthanum doped barium titanate. When processed in a particular way, this later material present at ambient temperature and at f = 1 kHz unusual interesting dielectric properties, a so called “colossal” permittivity value up to several 106 with relatively low dielectric losses. Moreover and contrary to what is classically expected and evidenced for this type of materials, no temperature dependence is observed. This behavior is observed in nanopowders based ceramics. An assumption to explain the observed properties is proposed. These results have important technological applications, since these nanoceramics open a new route to the fabrication of very thin dielectric films.

81 citations

Journal ArticleDOI
Seiji Ikegami1, Ichiro Ueda1
TL;DR: In this article, it was shown theoretically that the displacement of a 90°-wall towards the mechanically most stable position is proportional to the logarithm of time in the case of whisker crystal.
Abstract: Microscopic observation of the domain structure in polycrystalline BaTiO 3 is carried out. After the specimen is cooled down to room temperature through the Curie point the domain structure changes gradually from an initial irregular one to a final one consisting of fine stripes of 90°-domains. Such a change is named “90°-splitting.” The aging of dielectric constant may be due to an increase in clamping effect by the 90°-splitting. This “90°-splitting model” may explain also the agings in dielectric loss and hysteresis loop. The dielectric constant decreases linearly with logarithm of aging time. It was shown theoretically that the displacement of a 90°-wall towards the mechanically most stable position is proportional to the logarithm of time in the case of whisker crystal. The “logarithmic time dependence” of dielectric constant in polycrystalline specimen may be explained as due to the 90°-splitting which progresses at a rate proportional to logarithm of time.

81 citations

Journal ArticleDOI
TL;DR: In this paper, a new formulation is presented, which facilitates the evaluation of complex dielectric constant of low-loss materials by means of real equations, thus requiring only one-dimensional root search techniques.
Abstract: A widely used method for noncontact electromagnetic characterization of materials is based on the measurement of an insertion transfer function. This function, defined as the ratio of two phasor signals measured in the presence and absence of the material under test, is related to the dielectric constant of the material through a complex transcendental equation. Solving this equation requires a numerical two-dimensional root search technique, which is often time consuming due to slow convergence and the existence of spurious solutions. In this paper, a new formulation is presented, which facilitates the evaluation of complex dielectric constant of low-loss materials by means of real equations, thus requiring only one-dimensional root search techniques. Two sample materials are measured, and it is shown that their dielectric constants obtained from the exact complex equation and the new formulation are in excellent agreement. The new formulation reduces the computation time significantly and is highly accurate for the characterization of low-loss materials.

81 citations

Journal ArticleDOI
TL;DR: In this article, the authors have grown 5mol% MgO-doped multilayered Ba1−xSrxTiO3 (BST) films having a nominal thickness of 220nm with compositions of each layer as BST60/40, BST75/25, and BST90/10 (upgraded).
Abstract: We have grown 5mol% MgO-doped multilayered Ba1−xSrxTiO3 (BST) films having a nominal thickness of 220nm with compositions of each layer as BST60/40, BST75/25, and BST90/10 (upgraded). We also fabricated undoped upgraded BST and uniform BST60/40 films for comparison. Results show that Mg-doping improves dielectric loss (tanδ=0.008) and yields better surface roughness (∼3.1nm) compared to undoped upgraded BST. Mg-doped films displayed excellent temperature stability with temperature coefficient of capacitances of −0.94 and 1.14ppt∕°C from 20to90°C and 20to−10°C, respectively. Mg doping resulted in a moderate dielectric tunability (29%) compared to undoped BST (65.5%) at 444kV∕cm.

81 citations

Journal ArticleDOI
TL;DR: In this article, a review of microwave dielectric ceramics (MWDCs) sintered higher than 1000 from 2010 up to now, °C is presented.
Abstract: The explosive process of 5G communication evokes the urgent demand of miniaturized and integrated dielectric ceramics filter. It is a pressing need to advance the development of dielectric ceramics utilization of emerging technology to design new materials and understand the polarization mechanism. This review provides the summary of the study of microwave dielectric ceramics (MWDCs) sintered higher than 1000 from 2010 up to now, °C with the purpose of taking a broad and historical view of these ceramics and illustrating research directions. To date, researchers endeavor to explain the structure-property relationship of ceramics with multitude of approaches and design a new formula or strategy to obtain excellent microwave dielectric properties. There are variety of factors that impact the permittivity, dielectric loss, and temperature stability of dielectric materials, covering intrinsic and extrinsic factors. Many of these factors are often intertwined, which can complicate new dielectric material discovery and the mechanism investigation. Because of the various ceramics systems, pseudo phase diagram was used to classify the dielectric materials based on the composition. In this review, the ceramics were firstly divided into ternary systems, and then brief description of the experimental probes and complementary theoretical methods that have been used to discern the intrinsic polarization mechanisms and the origin of intrinsic loss was mentioned. Finally, some perspectives on the future outlook for high-temperature MWDCs were offered based on the synthesis method, characterization techniques, and significant theory developments.

81 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023396
2022863
20211,013
20201,000
20191,097
20181,012