Electrical/Dielectric Properties of Nanocrystalline Cerium Oxide

1996 ◽  
Vol 457 ◽  
Author(s):  
Jin-Ha Hwang ◽  
Thomas O. Mason ◽  
Edward J. Garboczi
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Transport Properties ◽  
Cerium Oxide ◽  
High Resistance ◽  
Current Flow ◽  
Impedance Spectra ◽  
Electrode Interface ◽  
Microcrystalline Material

ABSTRACTElectrical/dielectric properties of nanocrystalline cerium oxide have been studied using impedance spectroscopy, thermopower, and DC 4-point conductivity. The combined techniques identified the effect of poor electroding on impedance spectra. Incomplete contact between the specimen and the electrode induces an additional arc in the impedance spectra. The additional high resistance feature results from the geometric constriction of current flow at the specimen/electrode interface and can be misinterpreted as a grain boundary response. The defect chemistry, nonstoichiometry, and transport properties were investigated in nanoscale ceria and compared with those of microcrystalline material.

scholarly journals Separating bulk from grain boundary Li ion conductivity in the sol–gel prepared solid electrolyte Li1.5Al0.5Ti1.5(PO4)3

2015 ◽  
Vol 3 (42) ◽  
pp. 21343-21350 ◽  
Author(s):  
Stefan Breuer ◽  
Denise Prutsch ◽  
Qianli Ma ◽  
Viktor Epp ◽  
Florian Preishuber-Pflügl ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Ion Transport ◽  
Solid Electrolyte ◽  
Transport Properties ◽  
Low Temperatures ◽  
Sol Gel ◽  
Ion Conductivity ◽  
Li Ion ◽  
Ceramic Electrolytes

Impedance spectroscopy measurements down to very low temperatures allowed for resolving bulk ion transport properties in highly conducting ceramic electrolytes.

Dielectric properties of processed cheese

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chin Han Chan ◽  
Jean-Marc Saiter ◽  
Hubert Eudier ◽  
Hans-Werner Kammer
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Frequency Domain ◽  
Food Quality ◽  
Low Frequency ◽  
Relaxation Behavior ◽  
Impedance Spectra ◽  
Processed Cheese ◽  
Dynamic Studies

Abstract Dynamic studies of several processed cheeses were carried out for evaluation of their dielectric properties and their relaxation behavior. Impedance spectroscopy has been used to study the systems under discussion in low-frequency domain. A substantial number of impedance spectra will be given and discussed that relate the dielectric properties to food nutrients. Also influence of moisture on food quality might be evaluated.

Complex impedance spectroscopy and ionic transport properties of natural leucite, K0.90Na0.08[Al0.98Si2.02]O6, as a function of temperature and pressure

2010 ◽  
Vol 74 (3) ◽  
pp. 507-519 ◽  
Author(s):  
R. L. Jones ◽  
M. Thrall ◽  
C. M. B. Henderson
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Transport Properties ◽  
Complex Impedance ◽  
Ionic Transport ◽  
Ionic Mobility ◽  
Activation Energies ◽  
Complex Impedance Spectroscopy ◽  
Phase Assemblage ◽  
Temperature And Pressure

AbstractThe temperature (T) and pressure (P) dependence of dielectric and conductivity properties of natural leucite were determined using complex impedance spectroscopy at frequencies from 103 to 106 Hz. Experiments were carried out in a Walker multi-anvil cell at 1 atm and P from 2.5 to 6 GPa and at T from 350 to 800°C. At pressure >6 GPa and temperature >790°C the leucite broke down to kalsilite+sanidine and dielectric properties for this phase assemblage are given at 6.0–7.0 GPa and T to 1050°C.Leucite conductivity increases with increasing T and decreases with increasing P reflecting their different effects on migration of K cations within the channels in the leucite aluminosilicate framework. Activation energies for K+ migration in leucite increase with increasing pressure (0.74–0.97 eV; 70.0–93.2 kJ/mol) and activation volumes for leucite increase with increasing T (6.42–9.51 cm3/mol; 400–700°C). The latter data provide model K+ cation diameters increasing from 2.7 Å at 400°C to 3.2 Å at 700°C. These values are consistent with the earlier suggestion of Palmer and Salje that the ionic mobility mechanism consists of diffusion along <110> rather than along the main channels parallel to <111>.

Equivalent Circuit and AC conductivity of Sr1.75Co0.25P2O7 compound

2016 ◽  
pp. 3551-3556
Author(s):  
Adel Souissi ◽  
S. Guermazi
Keyword(s):  
Solid State ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Equivalent Circuit ◽  
Ac Conductivity ◽  
Solid State Reaction Method ◽  
Impedance Spectra ◽  
Reaction Method ◽  
Olpt Model ◽  
Approximation Type

Sr1.75Co0.25P2O7 compound was prepared by the solid-state reaction method. The impedance spectroscopy measurements were performed in the frequency and the temperature range of (209 Hz–1 MHz) and (622–704 K), respectively. Besides, the impedance spectra were fitted to an equivalent circuit consisting of series combination of grains and grain boundary. The AC conductivity for grain contribution is interpreted using the universal Jonscher’s power law. The approximation type OLPT model explains the universal behavior of the s exponent. The mechanism of conduction is probably due from the displacements of the Sr2+ ion in the tunnel-type cavities.

Dielectric Behaviour Of BaTiO3 Prepared By Sol–Gel Technique When Exposed To Different Oxygen Concentrations

2012 ◽  
Author(s):  
Cheow Keat Yeoh ◽  
Srimala Sreekantan ◽  
Sabar Derita Hutagalung ◽  
Zainal Arifin Ahmad
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Sol Gel ◽  
Chemical Processes ◽  
Oxygen Stoichiometry ◽  
Solution Ph ◽  
Gel Technique ◽  
Dta Curves ◽  
Oxygen Concentrations

Sifat dielektrik serbuk BaTiO3 yang disediakan melalui kaedah akues pada suhu rendah telah dikaji menggunakan kaedah spektroskopi impedans apabila didedahkan terhadap tahap oksigen yang berbeza. Untuk mengatasi masalah kebolehlarutan Ba dan Ti yang berbeza, nisbah sebatian Ba yang ditambah lebih tinggi daripada nisbah stoikiometri (tambahan 10%) dan nilai pH larutan yang tinggi (pH~13) diperlukan. Ujian XRD dan TGDTA menunjukkan BaTiO3 yang hampir tulen dapat disintesis melalui kaedah ini. Suhu pengkalsinan yang lebih tinggi menghasilkan darjah penghabluran bahan yang lebih tinggi. Kajian dielektrik menunjukkan bahan yang dihasilkan mengandungi lebih daripada satu elemen keelektrikan antaranya teras berkerintangan rendah, sempadan butiran berkapasitan tinggi dan suatu elemen pukal feroelektrik. Setelah didedahkan terhadap tahap oksigen yang lebih tinggi, nilai kerintangan sampel bertambah, yang mungkin disebabkan stoikiometri oksigen pada sampel yang diuji. Peningkatan dalam nilai kapasitan daripada sempadan butiran adalah lebih ketara jika dibandingkan dengan peningkatan unsur feroelektrik pukal. Kata kunci: Kaedah sol-gel, sintesis kimia, sifat dielektrik, BaTiO3 The dielectric properties of BaTiO3 powders prepared by a low temperature aqueous route when exposed to different oxygen concentrations have been studied by means of impedance spectroscopy. Due to the differences of solubility of Ba and Ti in aqueous solutions, deviations from stoichiometric ratios (a 10% excess) and higher solution pH (pH~13) were necessary. XRD traces and TG-DTA curves show the formation of nearly phase-pure BaTiO3 with higher calcinations temperatures promoting greater crystallinities. Dielectric measurements using impedance spectroscopy show the samples to consist of more than one electrical element including a low resistivity core, a high capacitance grain boundary and a ferroelectric bulk component. Exposing the samples to different oxygen concentrations caused a slight increase in resistivities with increasing oxygen concentration, which was attributed to the oxygen stoichiometry. A greater increase in the capacitance of the grain boundary component was also observed compared to the ferroelectric bulk. Key words: Sol-gel processes, chemical processes, dielectric properties, BaTiO3

Relaxation Behavior of Zr Substituted CaCu3Ti4O12 Ceramics

2011 ◽  
Vol 687 ◽  
pp. 375-379 ◽  
Author(s):  
Hong Tao Yu ◽  
Wen Bo Zhang ◽  
Jing Song Liu ◽  
Han Xing Liu
Keyword(s):  
Grain Size ◽  
Relaxation Time ◽  
Dielectric Properties ◽  
Grain Boundary ◽  
Dielectric Response ◽  
Relaxation Behavior ◽  
Impedance Spectra ◽  
Boundary Concentration ◽  
Giant Dielectric ◽  
Boundary Relaxation

The dielectric properties of Zr substituted CaCu3Ti4O12ceramics have been investigated in detail. Grain size decreases with Zr content increasing. The hetero-electrical microstructures of prepared samples have been confirmed by the impedance spectra. The dielectric loss has been improved by Zr doping because of the enhancement of grain boundary resistivity. A Debye-like boundary relaxation behavior has been observed in the temperature range of 220-600K. As Zr content increases, the relaxation time increases due to the higher grain boundary concentration. This work has provided an additional proof for the origin of giant dielectric response in CaCu3Ti4O12ceramics.

scholarly journals The Electric and Dielectric Properties of SrF2:Tb3+ Nanocrystals Revealed by AC Impedance Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Xiaoyan Cui ◽  
Tingjing Hu ◽  
Huangyu Wu ◽  
Junkai Zhang ◽  
Lihua Yang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Activation Enthalpy ◽  
Ac Impedance ◽  
Potential Scattering ◽  
Deformation Potential ◽  
Ac Impedance Spectroscopy ◽  
Low Frequencies ◽  
Sample Resistance

The electric and dielectric properties of SrF2:Tb3+ nanocrystals were studied by AC impedance spectroscopy. The grain and grain boundary resistances and the complex permittivity with different Tb-doped concentrations were obtained. As the Tb-doping concentration increases, the grain and grain boundary resistances decrease until 6% and then increase. The Tb doping leads to the increase of interstitial F− quantity and the decrease of the activation enthalpy, and finally causes the decreases of grain and grain boundary resistances. When the Tb-doping is larger than 6%, the effect of the deformation potential scattering is dominant, which leads to the increases of grain and grain boundary resistances. The strong dispersion of the permittivity at the low frequencies indicates the carrier was hopping in the transport process. The ε′ and ε″ values at the low frequencies decrease as the sample resistance increases.

Electrochemical Characterization of Phosphosilicate-modified Nafion Membranes

2004 ◽  
Vol 847 ◽  
Author(s):  
L. C. Klein ◽  
M. Aparicio
Keyword(s):  
Impedance Spectroscopy ◽  
Relative Humidity ◽  
Complex Impedance ◽  
Electrochemical Characterization ◽  
Hybrid Membranes ◽  
Impedance Spectra ◽  
Nafion Membranes ◽  
Electrode Interface ◽  
Interface Effects

ABSTRACTHybrid membranes containing Nafion and phosphosilicate gels were prepared using infiltration and recasting methods. The hybrid membranes were investigated using complex impedance spectroscopy. Conductivities were determined as a function of relative humidity. Infiltrated membranes, which contained gel in more or less discrete particles, were compared with recast membranes where the gel was more evenly distributed. Both of the modified membranes were compared to unmodified Nafion. The impedance spectra were analyzed to distinguish electrode interface effects from bulk transport phenomena.

scholarly journals Correction: Nafion film transport properties in a low-Pt PEM fuel cell: impedance spectroscopy study

RSC Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 6764-6765
Author(s):  
Tatyana Reshetenko ◽  
Andrei Kulikovsky
Keyword(s):  
Fuel Cell ◽  
Impedance Spectroscopy ◽  
Transport Properties ◽  
Pem Fuel Cell ◽  
Spectroscopy Study ◽  
Cell Impedance ◽  
Impedance Spectroscopy Study ◽  
Nafion Film

Correction for ‘Nafion film transport properties in a low-Pt PEM fuel cell: impedance spectroscopy study’ by Tatyana Reshetenko et al., RSC Adv., 2019, 9, 38797–38806, DOI: 10.1039/C9RA07794D.

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