scholarly journals An Electrode Setup for Non-contact Dielectric Response Measurement

2019 ◽  
pp. 88-93
Author(s):  
Jing Hao ◽  
Xiangdong Xu ◽  
Nathaniel Taylor
Keyword(s):  
Edge Effect ◽  
Dielectric Response ◽  
Measurement Instrument ◽  
Contact Problems ◽  
Dielectric Materials ◽  
Response Measurement ◽  
Fem Model ◽  
Electrode Arrangement ◽  
Conventional Electrode ◽  
Contact Electrode

The dielectric response measurement is a widely used technique for characterizing dielectric materials. However, the contact problems between samples and electrodes existing in the use of conventional electrode setup limit the accuracy of the measurement. This paper studies an electrode arrangement that avoids direct contacts of the sample with the electrodes on both sides. The edge effect of this arrangement is calculated by the FEM model. The equations to derive the complex permittivity are presented. The measurement instrument is described and the influence of the small voltage between its measure and guard terminals is analyzed. The error sensitivities of the non-contact and contact methods are compared. The results show that this electrode arrangement can be used to perform non-contact measurements, the edge effect of it is not significant, and the guard voltage is not an obstacle to obtain results with high accuracy. Overall, the non-contact electrode arrangement combined with the IDAX 300 can potentially improve the accuracy of dielectric response measurements although the non-contact methods can increase the sensitivities to errors.

scholarly journals Jonscher indices for dielectric materials

2019 ◽  
Vol 09 (06) ◽  
pp. 1950046
Author(s):  
C. L. Wang
Keyword(s):  
Experimental Data ◽  
Asymptotic Behavior ◽  
Dielectric Relaxation ◽  
Time Domain ◽  
Dielectric Response ◽  
Relaxation Function ◽  
Dielectric Materials ◽  
Dielectric Response Function ◽  
Barium Stannate ◽  
Two Parameters

Two parameters are proposed as Jonscher indices, named after A. K. Jonscher for his pioneering contribution to the universal dielectric relaxation law. Time domain universal dielectric relaxation law is then obtained from the asymptotic behavior of dielectric response function and relaxation function by replacing parameters in Mittag–Leffler functions with Jonscher indices. Relaxation types can be easily determined from experimental data of discharge current in barium stannate titanate after their Jonscher indices are determined.

TEMPERATURE DEPENDENCE OF THE n PARAMETER IN THE DISSADO–HILL MODEL

2013 ◽  
Vol 27 (06) ◽  
pp. 1350040 ◽  
Author(s):  
A. DOFF ◽  
J. C. GENTILINI ◽  
O. CAMBRUZZI
Keyword(s):  
Temperature Dependence ◽  
Quantum Electrodynamics ◽  
Dielectric Response ◽  
Dielectric Material ◽  
Dielectric Materials ◽  
Energy Scale ◽  
Dielectric Polarization ◽  
Hill Model ◽  
Running Coupling ◽  
Many Body Interactions

The response of a dielectric material to the application of an external electric field is characterized by the dependence of the complex dielectric polarization susceptibility on frequency ω and external factors such as temperature T. Even today, we do not have a universal model that describes the behavior for all materials. However, Dissado and Hill (DH) have proposed a model based on many-body interactions that is able to explain the dielectric response observed in many dielectric materials. By considering an analogy between the description given in the cluster approach to the structure of imperfect materials and the formalism developed in quantum field theory (QFT), particularly the scale invariance behavior displayed by the dependence of the running coupling constant of quantum electrodynamics (QED) on the energy scale Λ, we will include temperature dependence in the (n) and (m) parameters of the DH model to consider the effects of temperature on the dielectric response of some materials.

Selection guidelines for ionic dielectrics with gigantic dielectric response (GDR) based on polaronic phase transition criteria

2013 ◽  
Vol 1535 ◽  
Author(s):  
Valeri Ligatchev ◽  
Zhigen Yu ◽  
Jianwei Zheng ◽  
Michael B. Sullivan
Keyword(s):  
Phase Transition ◽  
Dielectric Response ◽  
Physical Nature ◽  
Dielectric Materials ◽  
Physical Mechanisms ◽  
Transition Criteria ◽  
Temperature Ranges ◽  
Experimental And Theoretical Studies ◽  
Very High ◽  
Selection Of

ABSTRACTDielectric materials with GDR (e.g. CaCu3Ti4O12 – CCTO and isostructural systems, co-doped NiO etc) attract major research interest due to their bright prospective in energy storage and memory devices. However, after years of intensive experimental and theoretical studies of GDR materials, physical nature of their extremely high complex dielectric permittivity (specifically, real part ∼ 104 - 106) is still not established convincingly. Another serious problem is excessively high imaginary part of the permittivity (which usually exceeds real one). Better understanding on physical mechanisms and limitations of GDR behavior in aforementioned dielectrics could be achieved based on polaronic phase transition criteria, proposed S. Fratini and P. Quémerais [Eur. Phys. Journ. B14, 99 (2000)]. In particular, ‘melting’ of Polaronic Wigner Crystal (PWC) either to ‘polaronic liquid’ or ‘electron liquid’ manifests two different scenarios of PWC phase transition at increment of concentrations of appropriate dopants. The former scenario is certainly preferable for ionic dielectrics with GDR behavior, while the latter one would yield in metal-like dielectric response with very high real permittivity, but unacceptable loss. Described approach provides physically transparent guidelines for selection of prospective host dielectrics with GDR behavior and quantitative estimations on critical dopant/polaron concentrations, corresponding to both aforementioned types of the phase transitions as well as temperature ranges suitable for GDR.

scholarly journals Influence of Mechanical, Thermal, and Electrical Perturbations on the Dielectric Behaviour of Guest-Encapsulated HKUST-1 Crystals

2020 ◽  
Author(s):  
Arun Babal ◽  
Jin-Chong Tan
Keyword(s):  
Dielectric Response ◽  
High Sensitivity ◽  
Dielectric Materials ◽  
Mechanical Stimuli ◽  
Operational Parameters ◽  
Materials Synthesis ◽  
Guest Molecules ◽  
A Value ◽  
Metal Organic ◽  
Chemical Selectivity

<p>Metal-organic frameworks (MOFs) are the emerging low-<i>k</i> dielectric materials for application in next-generation microelectronics and telecommunication devices. MOF dielectrics can function as smart sensors with high sensitivity and chemical selectivity, by leveraging the ubiquituous dielectric response of MOFs and overcoming the limitations of DC conductivity and fluorescence approaches. Herein we study the effects of materials synthesis, applied mechanical stress (37-520 MPa), varying temperature (20-100°C), and guest encapsulation on the frequency-dependent dielectric response (4 Hz to 1 MHz) and AC conductivity of the HKUST-1 MOF. Particularly, we show that the confinement of the triethylamine (NEt<sub>3</sub>) guest molecules in HKUST-1 (host) yields the NEt<sub>3</sub>@HKUST-1 system that is tuneable <i>via</i> mechanical, thermal and electrical perturbations. Within the frequency range of 10 kHz to 1 MHz, at 20 °C we show that the dielectric constant (𝜀‘) of the guest-encapsulated system could be tuned to attain a value of between 2.8 and 7.2; at 100 °C, an even greater range of 𝜀‘ from 3.1 to 9.5 could be achieved. Conversely, we found the dielectric tuneability of the porous (guest-free) HKUST-1 is relatively more limited (𝜀‘ = 2.8 to 4.9) whist employing the same operational parameters. Furthermore, the confinement of guest molecules in HKUST-1 enhances the mechanical resilience and yield strength of the powders subject to a compressive pelleting stress. Together, the results elucidate the new potential for exploiting host-guest interactions in MOFs, coupled with electro-thermo-mechanical stimuli to regulate the precise dielectric response of a designer low-<i>k</i> material.</p>

scholarly journals Thermal-Induced Dielectric Response In Mechanically Durable Polyvinylidene Fluoride/Tubular Kapok Fiber Encapsulated Polyethylene Glycol Composite Films

2021 ◽  
Author(s):  
Wenqi Wu ◽  
Xianglin Pei ◽  
Hairong Li ◽  
Junyang Tu ◽  
Qiong Li ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Dielectric Response ◽  
Polyvinylidene Fluoride ◽  
Composite Films ◽  
Dielectric Materials ◽  
Dielectric Susceptibility ◽  
Stable Operation ◽  
Kapok Fiber ◽  
Thermally Responsive ◽  
Mechanical Durability

Abstract Dielectric materials with thermally responsive property are being pursued in fields such as next-generation sensors, smart switches, and novel actuators. These applications require that the dielectric materials have mechanical durability and stable serviceability besides thermally responsive dielectric behavior. Herein, we report a novel thermally responsive, mechanically durable, and low-cost dielectric composite simply fabricated by vacuum impregnating polyethylene glycol (PEG) into Kapok fiber (KF) and compounding them with polyvinylidene fluoride (PVDF). A remarkable dielectric susceptibility, controlled dielectric transition temperature and obvious thermal hysteresis of the composite films induced by the solid-liquid phase transition of PEG are demonstrated. The effect of molecular weights of PEG on the dielectric response behaviors is evaluated. Such thermally responsive dielectric materials with satisfactory mechanical durability will offer a chance toward constructing thermally responsive systems for safe and stable operation.

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