scholarly journals Исследование пьезоэлектрического резонанса в стехиометрических кристаллах LiNbO-=SUB=-3-=/SUB=- в области высоких температур и проводимости

2019 ◽  
Vol 61 (7) ◽  
pp. 1277
Author(s):  
М.Н. Палатников ◽  
В.А. Сандлер ◽  
Н.В. Сидоров ◽  
О.В. Макарова
Keyword(s):  
Relaxation Time ◽  
Dielectric Properties ◽  
Lithium Niobate ◽  
High Temperatures ◽  
Piezoelectric Materials ◽  
Conductivity Relaxation ◽  
Static Conductivity ◽  
Piezoelectric Resonators ◽  
Wide Range ◽  
Conductivity Relaxation Time

In order to establish conditions of lithium niobate based piezoelectric resonators application at high temperatures and high conductivity in a wide range of temperatures (~ 300 – 850К) we have researched piezoelectric, ferroelectric, dielectric properties and ion conductivity of near-stoichiometric LiNbO3stoich crystals. We have revealed that piezo-resonance is observed in LiNbO3stoich in a certain temperature range ΔТ (correspondingly, in certain static conductivity relaxation time Δtau_V range) and frequencies range Δomega_R provided that tau_V-1<<omegaR. Such patterns are probably applicable not only to LiNbO3stoich crystals, but also to other piezoelectric materials.

Compliance of the Stokes–Einstein model and breakdown of the Stokes–Einstein–Debye model for a urea-based supramolecular polymer of high viscosity

Soft Matter ◽  
2014 ◽  
Vol 10 (42) ◽  
pp. 8457-8463 ◽  
Author(s):  
Jolanta Świergiel ◽  
Laurent Bouteiller ◽  
Jan Jadżyn
Keyword(s):  
Relaxation Time ◽  
High Viscosity ◽  
Debye Model ◽  
Dc Conductivity ◽  
Supramolecular Polymer ◽  
Conductivity Relaxation ◽  
Dipolar Relaxation ◽  
Einstein Model ◽  
Conductivity Relaxation Time ◽  
Hydrogen Bonded

Viscosity dependences of dc conductivity, conductivity relaxation time and dipolar relaxation time are measured for the neat hydrogen-bonded supramolecular polymer N,N′-di(2-ethylhexyl)urea (EHU).

scholarly journals Conductivity and Dielectric Behaviour Studies of LiCF3SO3 Dissociation in L-Chitosan/PMMA-Based Polymer Electrolytes

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
A.S.A Khiar ◽  
S. Mat Radzi ◽  
N. Abd Razak
Keyword(s):  
Relaxation Time ◽  
Dielectric Properties ◽  
Ionic Conductivity ◽  
Polymer Electrolytes ◽  
Room Temperature ◽  
Electrical Modulus ◽  
Solution Casting ◽  
Casting Method ◽  
Wide Range ◽  
Solution Casting Method

Lauroyl-chitosan/poly(methylmethacrylate)-lithium trifluorosulfonate (LiCF3SO3) polymer electrolytes has been prepared by the solution casting method. Ionic conductivity analysis was conducted over a wide range of frequency between 50 Hz-1 MHz using impedance spectroscopy to evaluate the dielectric properties and conductivity of the sample. Sample with 30 wt% of LiCF3SO3 showed the highest conductivity of 7.59 ± 3.64 x 10-4 Scm-1 at room temperature. Complex permittivity for real (εr), imaginary (εi) and electrical modulus for real (Mr) and imaginary (Mi) part was determined and plotted. The relaxation time, τ for these samples was determined and the plot shows that τ decreases with conductivity of the complexes.

AC Conductivity and Dielectric Properties of BiScO3–PbTiO3 Piezoelectric Ceramics

2021 ◽  
Vol 13 (9) ◽  
pp. 1807-1811
Author(s):  
Jae-Hoon Ji ◽  
Yoo-Young Oh ◽  
Bo Su Kim ◽  
Wook-Hee Han ◽  
Jung-Hyuk Koh
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Ac Conductivity ◽  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Ferroelectric Properties ◽  
Temperature Stability ◽  
Piezoelectric Ceramics ◽  
Dielectric Behavior ◽  
Wide Range

Bi-based BiMeO3 (where Me is a transition metal) has been extensively studied owing to its outstanding ferroelectric properties. The dielectric and electrical properties of piezoelectric ceramics can be enhanced by the addition of Bi-based materials such as BiAlO3, BiScO3 , and Bi(Mg, Ti)O3. Among them, BiScO3–PbTiO3 ceramics have shown excellent piezoelectric properties and temperature stability near the morphotropic phase boundary (MPB) region. Meanwhile, it is important to study the electrical properties of piezoelectric materials such as dielectric permittivity, conductivity of ferroelectric compounds, since dielectric and conductivities are related to pyroelectricity and piezoelectricity. In this study, the AC conductivity and dielectric properties of BiScO3–PbTiO3 ceramics were investigated with a wide range of frequencies and temperatures. Especially,the effect of PbTiO3 content on dielectric behavior of the BiScO3–PbTiO3 system was intensively studied by impedance spectroscopy.

Study of Motion of Impurity Ions Making Influence on Electrical Properties of Polymer Solids in Low Frequency Range

2013 ◽  
Vol 740 ◽  
pp. 630-635 ◽  
Author(s):  
Yui Chi Anada
Keyword(s):  
Relaxation Time ◽  
Electrical Properties ◽  
Low Frequency ◽  
Dioctyl Phthalate ◽  
Conductivity Relaxation ◽  
Impurity Ions ◽  
Free Spaces ◽  
Poly Ethylene ◽  
Poly Propylene ◽  
Conductivity Relaxation Time

The motion of impurity ions affects the electrical properties of polymer solid. The ions move through free spaces which exist in the non-crystalline part between polymer crystallites. The free spaces have inhomogeneous size distribution depending on a property of polymers or crystallization conditions. The homogeneity or inhomogeneity of the size of the free space affects the ionic motion, and consequently it also affects the electrical properties of polymer solids. In order to study the electrical properties of polymer solids in relation with such motion of impurity ions, the conductivity relaxation time was calculated for isotactic poly (propylene) (iPP), low density poly (ethylene) (LDPE) and plasticized poly (vinyl chloride) with dioctyl phthalate (p-PVC) from the electric modulus as a function of frequency which was observed by means of the Broadband Dielectric Spectroscopy (BDS). The value of the conductivity relaxation time reflects the non-crystalline structure of these polymers.

scholarly journals Enhancement of piezoelectric properties of lithium niobate thin films by different annealing parameters

2020 ◽  
Vol 6 (2) ◽  
pp. 47-52
Author(s):  
Roman N. Zhukov ◽  
K.S. Kushnerev ◽  
Dmitry A. Kiselev ◽  
Tatiana S. Ilina ◽  
Ilya V. Kubasov ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Silicon Substrate ◽  
Optical Waveguides ◽  
Piezoelectric Materials ◽  
Random Access ◽  
Piezoelectric Phase ◽  
Electro Optic ◽  
Wide Range ◽  
Probe Microscope ◽  
Ferroelectric Random Access Memories

Piezoelectric materials with useful properties find a wide range of applications including opto- and acousto- electronics. Lithium niobate in the form of a thin film is one of those promising materials and has a potential to improve ferroelectric random access memories devices, optical waveguides or acoustic delay lines by virtue of its physical characteristics, e.g. electro-optic coefficient, acoustic velocity, refractive indices etc. The key challenge to overcome is lithium nonstoichiometry as it leads to the appearance of parasite phases and thus aggravates physical and structural properties of a film. According to literature data, in order to obtain microcrystalline piezoelectric phase in previously amorphous films a set of methods is used. In our case we tried to synthesize LN films using congruent target and non-heated silicon substrate and then attain the piezoelectric phase by different annealing parameters. Afterwards LN films were compared to the ones synthesized on the silicon substrate with an additional buffer layer of platinum. Samples were studied by scanning probe microscope. Self-polarization vectors were defined. Based on domain structure images, the histograms of distribution of piezoresponse signals were built.

Conductivity Vs Nmr Correlation Times, and Decoupled Cation Motion in Polymer-In-Salt Electrolytes

1992 ◽  
Vol 293 ◽  
Author(s):  
Jiang Fan ◽  
R.F. Marzke ◽  
C.A. Angeill
Keyword(s):  
Relaxation Time ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Conductivity Relaxation ◽  
Spin Lattice ◽  
Low Salt ◽  
Cation Matrix ◽  
Pure Salt ◽  
Conductivity Relaxation Time

AbstractWe report 7Li spin lattice relaxation times at 12.82 MHz over a range of temperatures for liquid electrolytes of various salt:polymer ratios, and compare the NMR correlation time obtained at the temperature of the T1 minimum with the conductivity relaxation time at the same temperature. We find that at low salt contents the two relaxation times have the same value, but beyond the “salt-inpolymer to polymer-in-salt transition” zone at the Tg maximum, the two times increasingly separate. This is taken as evidence for the onset of cation-matrix mobility decoupling, which maximizes at the pure salt extreme.

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