Influence of Bi-site Substitution on the Ferroelectricity of the Aurivillius Compound Bi2SrNb2O9

1998 ◽  
Vol 13 (9) ◽  
pp. 2565-2571 ◽  
Author(s):  
P. Durán-Martín- ◽  
A. Castro ◽  
P. Millán ◽  
B. Jiménez
Keyword(s):  
Dielectric Constant ◽  
Electric Conductivity ◽  
Remanent Polarization ◽  
Hysteresis Loops ◽  
Relaxor Behavior ◽  
Paraelectric Phase Transition ◽  
Thermally Activated ◽  
Coupling Factors ◽  
Higher Temperature ◽  
First Time

Ceramics based on the composition Bi2SrNb2O9 with isomorphic substitutions of cations in the Bi2O22+ and the perovskite layers, Bi2−xTexSr1−xNa(K)xNb2O9, have been prepared by solid state reaction. The ferroelectricity of this Aurivillius type structure has been studied. Dielectric measurements as a function of the temperature show a low temperature maximum in the dielectric constant that would correspond to a ferro-;paraelectric phase transition. The temperature of this maximum increases when the radius of the ion that substitutes Sr for decreases. A second maximum in the dielectric constant is found at higher temperature possibly corresponding to a relaxor ferroelectric. Measurements of remanent polarization as a function of the temperature seem to confirm the relaxor behavior, because the polarization disappears at temperatures between the two maxima of the dielectric constant. Saturated hysteresis loops are obtained for all the substituted samples at temperatures above 300 °C. Ferroelectric parameters such as the polarization, coercive field, and coupling factors of the BSN family compounds were obtained for the first time. The ac electric conductivity shows anomalies at temperatures close to those where the remanent polarization disappears. Activation energies calculated from measurements of dc electric conductivity, impedance arcs, and dielectric modulus data may be associated with thermally activated oxygen vacancies.

Growth of Epitaxial Potassium Niobate Film on (100)SrRuO3/(100)SrTiO3 by Hydrothermal Method and their Electromechanical Properties

2008 ◽  
Vol 1139 ◽  
Author(s):  
Mutsuo Ishikawa ◽  
Shintaro Yasui ◽  
Satoshi Utsugi ◽  
Takashi Fujisawa ◽  
Tomoaki Yamada ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Hydrothermal Method ◽  
Remanent Polarization ◽  
Bottom Electrode ◽  
Hysteresis Loops ◽  
Relative Dielectric Constant ◽  
Ultrasonic Waves ◽  
Potassium Niobate ◽  
Electromechanical Properties

AbstractEpitaxaially-grown KNbO3 thick films over 8 μm in thickness were successfully grown at 220 °C for 6 h on (100)cSrRuO3//SrTiO3 substrates by a hydrothermal method. Epitaxial SrRuO3 layers grown on (100)cSrTiO3 substrates by sputter method were used as bottom electrode layers. Relative dielectric constant and the dielectric loss were 530 and 0.11, respectively. Clear hysteresis loops originated to the ferreoelectricity were observed and a remanent polarization was 25 μC/cm2 at a maximum applied electric field of 540 kV/cm. In addition, the hydrothermal KNbO3 thick film was able to transmitting and receiving of ultrasonic waves over 50MHz.

scholarly journals Effect of Composition on Polarization Hysteresis and Energy Storage Ability of P(VDF-TrFE-CFE) Relaxor Terpolymers

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1343
Author(s):  
Yusra Hambal ◽  
Vladimir V. Shvartsman ◽  
Daniil Lewin ◽  
Chieng Huo Huat ◽  
Xin Chen ◽  
...  
Keyword(s):  
Energy Storage ◽  
Hysteresis Loops ◽  
Freezing Temperature ◽  
Relaxor Behavior ◽  
Ferroelectric State ◽  
Storage Performance ◽  
Relaxor State ◽  
A Charge ◽  
First Time ◽  
Discharge Efficiency

The temperature dependence of the dielectric permittivity and polarization hysteresis loops of P(VDF-TrFE-CFE) polymer films with different compositions are studied. Among them, the three compositions, 51.3/48.7/6.2, 59.8/40.2/7.3, and 70/30/8.1, are characterized for the first time. Relaxor behavior is confirmed for all studied samples. Increasing the CFE content results in lowering the freezing temperature and stabilizes the ergodic relaxor state. The observed double hysteresis loops are related to the field-induced transition to a ferroelectric state. The critical field corresponding to this transition varies with the composition and temperature; it becomes larger for temperatures far from the freezing temperature. The energy storage performance is evaluated from the analysis of unipolar polarization hysteresis loops. P(VDF-TrFE-CFE) 59.8/40.2/7.3 shows the largest energy density of about 5 J·cm−3 (at the field of 200 MV·m−1) and a charge–discharge efficiency of 63%, which iscomparable with the best literature data for the neat terpolymers.

Electrical Properties of the Mixed Bismuth Layer-Structured Bi7Ti4NbO21 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 255-258 ◽  
Author(s):  
Lina Zhang ◽  
Guo Rong Li ◽  
Su Chuan Zhao ◽  
Liao Ying Zheng ◽  
Qing Rui Yin
Keyword(s):  
Remanent Polarization ◽  
Piezoelectric Coefficient ◽  
Hysteresis Loops ◽  
Test System ◽  
Orthorhombic Symmetry ◽  
Thermal Dependence ◽  
Paraelectric Phase Transition ◽  
Two Phase ◽  
Conventional Solid State Reaction ◽  
X Ray

A mixed bismuth layer-structured compound, Bi7Ti4NbO21, has been prepared by the conventional solid state reaction. It showed an orthorhombic symmetry with a = 5.4428, b = 5.4043 and c = 29.041 Å by X-ray powder diffraction analysis. The hysteresis loops as a function of temperature were observed with a standardized ferroelectric test system. The remanent polarization and the coercive field of the material at 140°C were 14.06 µC/cm2 and 78.6 kV/cm, respectively. Thermal dependence of dielectric permittivity showed two-phase transitions at around 670°C and 845°C, which were also investigated by TSC and DSC. Finally, piezoelectric properties were obtained with a piezoelectric coefficient d33 = 10 pC/N. It was observed that Bi7Ti4NbO21 underwent a ferroelectric–paraelectric phase transition at 845°C by depolarization experiments.

Dielectric abnormity of Sr4Nd2Ti4Nb6O30 tungsten bronze ceramics over a broad temperature range

2007 ◽  
Vol 22 (8) ◽  
pp. 2217-2222 ◽  
Author(s):  
X.L. Zhu ◽  
X.M. Chen ◽  
X.Q. Liu
Keyword(s):  
Tungsten Bronze ◽  
Freezing Temperature ◽  
Broad Temperature Range ◽  
Maximum Temperature ◽  
Relaxor Behavior ◽  
Temperature Range ◽  
Thermally Activated ◽  
Higher Temperature ◽  
Tan Δ ◽  
Lower Temperature

In the present paper, Sr4Nd2Ti4Nb6O30 ceramics with filled tungsten bronze structure were prepared, and the dielectric characteristics over a broad temperature range (123 to 623 K) were investigated. Two dielectric abnormities were observed in the entire frequency range (100 Hz to 1 MHz). One is at higher temperature corresponding to a diffuse ferroelectric transition (P4/mbm → P4bm), and the other at lower temperature shows relaxor characteristics in both ϵ′ and tan δ curves. An activation energy and freezing temperature of 0.1659 eV and 148.05 K, respectively, were obtained by analyzing the frequency dependence of the dielectric maximum temperature using the Vogel–Fulcher relationship. The relaxor behavior is attributed to a polar-glassy system with thermally activated polarization fluctuations above the freezing temperature. In addition, the dielectric constant was almost stable with both temperature and frequency in the temperature range of 300 to 430 K (between the two dielectric abnormities).

Variable Temperature Measurement on Operating Pentacene-Based OTFT

2008 ◽  
Vol 1091 ◽  
Author(s):  
Hung-Keng Chen ◽  
Po-Tsun Liu ◽  
Ting-Chang Chang ◽  
S.-L. Shy
Keyword(s):  
Conduction Mechanism ◽  
Variable Temperature ◽  
Electrical Measurement ◽  
Isokinetic Temperature ◽  
Trap States ◽  
Band Tail ◽  
Thermally Activated ◽  
Multiple Trapping ◽  
Higher Temperature ◽  
Release Model

AbstractVariable temperature electrical measurement is well-established and used for determining the conduction mechanism in semiconductors. There is a Meyer¡VNeldel relationship between the activation energy and the prefactor with a Meyer¡VNeldel energy of 30.03 meV, which corresponds well with the isokinetic temperature of about 350 K. Therefore, the multiple trapping and release model is properly used to explain the thermally activated phenomenon. By the method, an exponential distribution of traps is assumed to be a better representation of trap states in band tail. Samples with higher temperature during measurement are observed to show better mobility, higher on-current and lower resistance, which agree well with the multiple trapping and release model proposed to explain the conduction mechanism in pentacene-based OTFTs.

scholarly journals Thickness-dependent electrocaloric effect in mixed-phase Pb 0.87 Ba 0.1 La 0.02 (Zr 0.6 Sn 0.33 Ti 0.07 )O 3 thin films

2016 ◽  
Vol 374 (2074) ◽  
pp. 20160056 ◽  
Author(s):  
T. M. Correia ◽  
Q. Zhang
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Phase Transitions ◽  
Film Thickness ◽  
Tetragonal Phase ◽  
Sol Gel ◽  
Breakdown Field ◽  
Electrocaloric Effect ◽  
Thickness Increase ◽  
Higher Temperature

Full-perovskite Pb 0.87 Ba 0.1 La 0.02 (Zr 0.6 Sn 0.33 Ti 0.07 )O 3 (PBLZST) thin films were fabricated by a sol–gel method. These revealed both rhombohedral and tetragonal phases, as opposed to the full-tetragonal phase previously reported in ceramics. The fractions of tetragonal and rhombohedral phases are found to be strongly dependent on film thickness. The fraction of tetragonal grains increases with increasing film thickness, as the substrate constraint throughout the film decreases with film thickness. The maximum of the dielectric constant ( ε m ) and the corresponding temperature ( T m ) are thickness-dependent and dictated by the fraction of rhombohedral and tetragonal phase, with ε m reaching a minimum at 400 nm and T m shifting to higher temperature with increasing thickness. With the thickness increase, the breakdown field decreases, but field-induced antiferroelectric–ferroelectric ( E AFE−FE ) and ferroelectric–antiferroelectric ( E FE−AFE ) switch fields increase. The electrocaloric effect increases with increasing film thickness. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’.

Synthesis and Ferroelectric Properties of Sol–Gel Derived Intergrowth-Superlattice-Structured SrBi4Ti4O15-Bi4Ti3O12 Thin Films

2011 ◽  
Vol 197-198 ◽  
pp. 1781-1784
Author(s):  
Hua Wang ◽  
Jian Li ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Annealing Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Si Substrates ◽  
Gel Processing ◽  
Coercive Electric Field ◽  
Clockwise Hysteresis

Intergrowth-superlattice-structured SrBi4Ti4O15–Bi4Ti3O12(SBT–BIT) films prepared on p-Si substrates by sol-gel processing. Synthesized SBT–BIT films exhibit good ferroelectric properties. As the annealing temperature increases from 600°C to 700°C, the remanent polarization Prof SBT–BIT films increases, while the coercive electric field Ecdecreases. SBT–BIT films annealed at 700°C have a Prvalue of 18.9µC/cm2which is higher than that of SBT (16.8µC/cm2) and BIT (14.6µC/cm2), and have the lowest Ecof 142 kV/cm which is almost the same as that of SBT and BIT. The C-V curves of Ag/SBT-BIT/p-Si heterostructures show the clockwise hysteresis loops which reveal the memory effect due to the polarization. The memory window in C-V curve of Ag/SBT-BIT/p-Si is larger than that of Ag/SBT/p-Si heterostructure or Ag/BIT/p-Si heterostructure.

scholarly journals Synthesis and electrical characterization of Ca2Nd4Ti6O20 ceramics

2016 ◽  
Vol 34 (1) ◽  
pp. 164-168
Author(s):  
Raz Muhammad ◽  
Muhammad Uzair ◽  
M. Javid Iqbal ◽  
M. Jawad Khan ◽  
Yaseen Iqbal ◽  
...  
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Room Temperature ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Sintered Sample ◽  
First Time ◽  
Alkoxide Precursors ◽  
Room Temperature Dielectric Constant

AbstractCa2Nd4Ti6O20, a layered perov skite structured material was synthesized via a chemical (citrate sol-gel) route for the first time using nitrates and alkoxide precursors. Phase analysis of a sample sintered at 1625 °C revealed the formation of an orthorhombic (Pbn21) symmetry. The microstructure of the sample after sintering comprised rod-shaped grains of a size of 1.5 to 6.5µm. The room temperature dielectric constant of the sintered sample was 38 at 100 kHz. The remnant polarization (Pr) and the coercive field (Ec) were about 400 μC/cm2 and 8.4 kV/cm, respectively. Impedance spectroscopy revealed that the capacitance (13.7 pF) and activation energy (1.39 eV) of the grain boundary was greater than the capacitance (5.7 pF) and activation energy (1.13 eV) of the grain.

RBS/Channeling Diffusion Studies of High Energy Au Implanted Mg Single Crystals

1991 ◽  
Vol 235 ◽  
Author(s):  
R. C. Da Selva ◽  
M. F. Da Silva ◽  
L. Thomé ◽  
A. A. Melo ◽  
J. C. Soares
Keyword(s):  
Single Crystals ◽  
Temperature Regime ◽  
High Energy ◽  
Back Diffusion ◽  
Thermally Activated ◽  
Diffusion Studies ◽  
Higher Temperature ◽  
Diffusion Behaviour ◽  
Thermally Activated Process

ABSTRACTRBS/channeling analyses of high energy Au implantation into Mg are presented. The diffusion behaviour of Au was studied and the occurrence of essentially two distinct regimes were observed: the segregation regime at lower temperatures correlated with the damage introduced by the high energy implantation and the higher temperature regime as a normal thermally activated process of back-diffusion.

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