Dielectric Hysteresis Loops Research Articles

Energy storage performance and dielectric tunability of AgNbO3 ferroelectric films

AgNbO3 ceramics have attracted significant attention as environmentally friendly energy storage materials; however, their low energy densities limit further development. In this study, a 400- nm AgNbO3 films with a dense microstructure and flat surface is prepared by pulsed laser deposition. The dielectric tenability and hysteresis loops of the film reveal its ferroelectric nature. The dielectric tunability of the AgNbO3 film was 63.6% at 600kV/cm. The breakdown strength reached 1500kV/cm, resulting in a high recoverable energy density of 13.3J/cm3. The recoverable energy storage density of AgNbO3 films indicates good temperature stability with a variation of < 10% between 30 ℃ and 150 ℃ and good frequency stability with a variation of < 10% between 103Hz and 105 Hz. These results suggest that AgNbO3 dielectric films are promising energy storage materials.

Anion-substituted Hybrid Zinc Halides with Remarkable Dielectric Switches.

Thermo-responsive dielectric switching hybrid halides, displaying reversible dielectric bistability, have recently made them highly versatile and attractive for their structural tunability and rich functional properties. However, the substantial improvement of the dielectric switching operating range is limited near room temperature, and obtaining ultra-wide dielectric switching temperature region is a major challenge. Herein, a remarkable dielectric switching effect is reported with ultra-wide dielectric switching temperature region in a hybrid halide system, caused by dipolar orientational polarization ascribing order-disorder phase transitions. The new A2BX4 hybrid halide [C6H5(CH2)4NH3]2ZnBr4 (4PBA-ZnBr4) with an ultra-wide dielectric hysteresis loop of about 55 K near room temperature is designed successfully through halogen substitution. Meanwhile, structurally similar hybrid materials 4PBA-ZnI4 were designed as controls. More interestingly, the crystal structure, phase transition temperature (Tc), dielectric and semiconductor properties exhibit significant discrepancies as the halogen atoms vary from Br to I. This discovery provides an efficiently regulated anionic framework to construct hybrid halides with ultra-wide high dielectric switching and reliable cycling stability by assembling with various cations, making them potentially excellent candidates for highly responsive room temperature smart switches or transducer devices.

Analysis of hysteresis loops and dielectric performance in the ovalene-like system: Monte Carlo study

This Monte Carlo study offers a comprehensive analysis of the ovalene-like system, emphasizing its dielectric behavior, thermal performance and hysteresis loops. The investigation reveals intricate dynamics influenced by diverse parameters, contributing to a nuanced understanding of the system’s response. Additionally, the study scrutinizes the impact of various physical parameters on the thermal behavior of polarizations and susceptibilities. The examination thoroughly explores the influence of these parameters on loop characteristics, coercive field, and saturation behavior, unveiling the formation of multiple loops and polarization plateaus on the electric hysteresis. In summary, this study advances our understanding of the ovalene-like system’s dielectric response, thermal characteristics and hysteresis dynamics, providing valuable insights for future research and applications, particularly in advanced electronic devices.

Energy storage and dielectric properties in PbZrO3/PbZrTiO3 antiferroelectric/ferroelectric bilayer bulk structure using Landau theory

Employing Landau theory and the Landau–Khalatnikov (L–K) equation of motion, we investigate the phase transitions in individual layers of antiferroelectric lead zirconate (PbZrO3), ferroelectric lead zirconate titanate (PbZrTiO3), and an antiferroelectric/ferroelectric PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer bulk structure. We examine the dielectric hysteresis loop behavior of the three systems, with a specific focus on the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer under different stabilities of the PbZrO3 layer. In addition, we explore cases where the coercive field of the bilayer structure is lower than that of the PbZrTiO3 individual layer. The recoverable electric energy for the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer increases significantly to 118 J/cm3 at an applied field of 7.5 × 108 V/m at 20 °C. In comparison, the PbZr(0.21)Ti(0.79)O3 layer reaches 71.8 J/cm3 under the same field and temperature conditions. This is much higher than those predicted experimentally by previous studies on thin film single and bilayer structures (15.6 and 28.2 J/Cm3 respectively), indicating that the antiferroelectric/ferroelectric PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer bulk structure could be used to target specific large-scale, long-term energy storage applications. Upon increasing the value of the coupling coefficient, the transition temperatures of the PbZrO3 layer and the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer are increased up to the transition temperature of the PbZr(0.21)Ti(0.79)O3 individual layer (450 °C). This increment in the transition temperature in the bilayer system contributes to its stability in storing energy at higher temperatures. Furthermore, the recoverable energy density of the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer increases further with temperature from 20 to 440 °C correlated with the rise in the difference between the spontaneous and the remanent polarizations (Ps − Pr). The significant stored energy observed over a wide temperature range highlights the promise of this bilayer structure for creating high-power capacitors where stability at different temperatures is crucial and possesses greater energy storage capacity.

Large Polaron Condensation in a Pseudo-Bilayer Quantum Hall Composite.

There is much interest regarding the "coupled ferroelectricity and superconductivity" in the two-dimensional material, bilayer Td-MoTe2; however, the value and the type of electric polarization are unknown. The device structure and the measurement method show that the measured material is the composite of the pseudo-bilayer quantum Hall system, with a thickness of about thirty-six nanometers. The derived dielectric hysteresis loops and the calculated electronic structure reveal that the condensed large polarons are responsible for the reverse ferroelectricity and the coupled superconductivity. The maximum value of polaron-type electric polarization is ~12 nC/μm2 or 1.2 × 104 μc/cm2.

Quasipolaron surface states in antiferromagnetic dielectrics

Dynamic responses of copper titanates to alternating electric fields with different strengths are characterized in terms of dielectric spectrums. This work extends the introduction of quasipolaron surface polarization (QSP). A collective of quasipolarons pinned at grain surfaces is involved in the electric polarization, which is confirmed by the quadratic polarization–permittivity relation. Because electric polarization is a macroscopic quantum effect, the QSP is described in terms of the density of states (DOS). As a sign of reverse ferroelectricity, dielectric hysteresis loops of reverse-S shape reveal that the characteristic remnant polarization is proportional to the DOS ratio of quasipolaron surface excited to ground states. Although the DOS of the surface ground state is dependent on the mole ratio of quasipolaron quantity, both the DOS and the energy levels of surface excited states show the intrinsic angular-frequency dependence in a power function manner.

Scale transition and residual fields in modeling of polycrystalline ferroelectrics based on the internal energy potential and a Voigt–Reuss approximation

A multiscale constitutive model, implemented within a semi-analytical computational framework, is presented. Accounting for domain switching in a tetragonal lattice and electromechanical intergranular interactions, it aims to accurately reproduce experimental data available from butterfly and dielectric hysteresis loops. For the sake of validation, these have been collected from various sources providing ranges of values for characteristic quantities. Adopting the fundamental ideas of a previously published model, a different homogenization approach is employed for the transition from grain to polycrystalline domain, providing both residual stress and electric fields. Furthermore, the thermodynamic driving force and constitutive equations on the grain level are based on a different thermodynamical potential. While the modeling approach inherently does not include any tuning parameters, the introduction of one and two, respectively, additional parameters is investigated, although computational results are basically in good agreement with experimental ranges.

Effect of a Metallic Implant on the Hysteresis of Ferroelectric BaTiO3 Ceramics

The dielectric constant and hysteresis loops of BaTiO3 ceramics with and without Pt implants were compared to determine the effect of the implant on the ceramic behavior. Ceramics with 90% relative density and 13.28 µm average grain size were analyzed. The results showed alterations in the ceramic’s coercive field, remanent polarization, and dielectric constant with an implant. The metallic implant affected the internal structure of the BaTiO3 ceramic, which reduced the ferroelectric properties of the material. In principle, these alterations can be seen as drawbacks, but they open new applications. The results provide insights into the real impact of metallic implants on the ferroelectric properties of the samples.

Amino-acid Based Ferroelectric Nanocomposites from Glycine Sodium Nitrate and Nanodispersed Silicon Dioxide: Preparation, Structure and Electrophysical Properties

For the first time, the nanocomposites from glycine sodium nitrate (GSN) and nanoparticles of silicon dioxide (nSiO2) have been synthesized using a slow evaporation technique. Observed that the optimal content of nSiO2 was estimated as 16.7 wt.%, any deviation from which affected the growth of GSN crystals in the composite, phase transition temperature, dielectric constant, and characteristics of dielectric hysteresis loops. All the anomalies will be thoroughly explained with the evidence of structural data of X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR).

Triple and double hysteresis loops in relaxor ferroelectric PMN-0.28PT crystals

The evolution of the dielectric hysteresis loops shape during heating of PMN-0.28PT single crystals possessing rhombohedral symmetry at room temperature was studied in the temperature range from room temperature to 200 °C. Revealed formation of the triple and double dielectric hysteresis loops in the relaxor phase upon switching by an electric field was explained by the influence of depolarizing fields arising at the interface of non-polar inclusions, and by the ineffective screening of polar clusters forming during transition through a percolation threshold, correspondingly. Further size decrease in the polar clusters due to heating led to their transformation to polar nanoregions.

Effects of Composition and Compression Pressure on the Ferroelectricity of a Novel Eco-Friendly Nanocomposite Based on a Molecular Ferroelectric of Tris-Sarcosine Calcium Chloride Filled with Cellulose Nanoparticles

For the first time, to our knowledge, an eco-friendly nanocomposite based on a classical molecular ferroelectric of Tris-sarcosine calcium chloride (TSCC) with an addition of cellulose nanoparticles (CNPs) was synthesized. The samples containing different cellulose concentrations were compressed under various pressures from 0.1 to 0.7 GPa to investigate the effects of composition and compression pressure on the ferroelectricity of the composites. Experiments were conducted on samples in the fresh state and after 200 h under normal conditions. The results obtained demonstrated higher phase transition temperatures in the composites than those of pure TSCC. Besides, a deformation of the dielectric hysteresis loops with changing cellulose content was detected. Importantly, an increase in compression pressure applied on the samples led to the movement of the phase transition point toward higher temperatures. The results also revealed an instability of the ferroelectric properties in the composites with high content of cellulose.

Evolution of phase transitions and energy storage effect in SrTiO_3-PbZrO-=SUB=-3-=/SUB=- solid solutions

Solid solutions (1-x)SrTiO3-xPbZrO3 (x=0.5, 0.6, 07, 0.8, 0.9) were synthesized and their dielectric properties are investigated Measurement of dielectric hysteresis loops allowed us to obtain field dependences of the main parameters characterizing the effect of energy storage in these materials. The relationship of the obtained parameters with the evolution of the state of solid solutions from relaxors to antiferroelectrcs in this system is discussed. Keywords: solid solutions, energy storage effect, relaxors, antiferroelectrcs.

Процессы переключения в керамике твердых растворов на основе Ca-=SUB=-0.3-=/SUB=-Ba-=SUB=-0.7-=/SUB=-Nb-=SUB=-2-=/SUB=-O-=SUB=-6-=/SUB=-

In this work, ceramic samples with a structure of the type of tetragonal tungsten bronzes, composition Са0.3Ba0.7Nb2O6 (CBN30) pure and with modifying additives SrTiO3, KTaO3 or LiTaO3 (5 mass %) were studied by the oscillographic method. It is shown that the introduction of modifying additives into CBN30 ceramics leads to an increase in the reversal polarization and to a decrease in dielectric losses, both at room temperature and at high temperatures. The introduction of LiTaO3 impurity into the CBN30 composition leads to the greatest increase in the reversal polarization. In contrast to ceramics based on lead zirconate titanate, which have a perovskite type structure, the introduction of SrTiO3 into CBN30 (having the structure of tetragonal tungsten bronzes) does not significantly improve the ferroelectric properties. It has been found that at temperatures above 100 °C for pure CBN30 ceramics, above 165 °C for CBN30 + 5% SrTiO3 and CBN30 + 5% KTaO3, and above 200 оС for CBN30 + 5% LiTaO3, there is a strong increase in dielectric losses. The contribution of dielectric losses to switching processes makes it impossible to determine the temperature of the ferroelectric phase transition for solid solutions based on CBN30 from the temperature dependences of dielectric hysteresis loops.

Thermal evolution of stillwellite, CeBSiO5, a natural prototype for a family of NLO-active materials

Stillwellite, ideally CeBSiO5, is a rare mineral, however, its discovery stimulated the intense studies of a new class of stillwellite-like materials with remarkable electrical and optical properties. With the use of the modern non–ambient single crystal X-ray diffraction, this work sheds some light on the evolution of stillwellite crystal structure during the process of high-temperature transformations noted for the most of these practically important compounds. Here a sample of natural stillwellite [stillwellite-(Ce)] from the Darai-Pioz alkaline massif (Tadjikistan) has been studied by means of electron microscopy, IR spectroscopy, single crystal and powder X-ray diffraction (XRD) in a wide temperature range from −180 up to 1200 ​°C. The dielectric properties are also measured in the range from −180 up to 500 ​°C. The low (LT) and the high temperature (HT) structure deformation and transformation are described from single XRD data including the detail analysis of deformation of cationic polyhedra on heating. The disorder-to-order phase transition occurs in the stillwellite structure at about 450–500 ​°C. Both LT (disordered) and HT (ordered) modifications are characterized as relatively low expansion materials: αvolume ​= ​15 and 19 ​× ​10-6 °C-1 for LT and HT phases, respectively. The high-temperature transformation of stillwellite involves some negative thermal expansion (αvolume ​= ​−11 ​× ​10-6 ​°C-1) caused by order-disorder process and presumably by the partial oxidation of Ce3+ to Ce4+. The dielectric properties show a maximum in the region of transformation as well, but the study of dielectric hysteresis loops did not confirm the ferroelectric order of stillwellite structure at room temperature. The high-temperature behavior and the decomposition process of stillwellite are dictated by the partial oxidation of cerium.

Anomalous P-E Hysteresis Loops of Ferroelectric Nanocomposites Containing Nanocellulose and Hydrogen – Bonded Ferroelectric of Triglycine Sulfate Under Influence of Composition, Temperature and Moisture

To fill the gap of earlier works for the nanocomposite based on a ferroelectric of triglycine sulfate (TGS) and a dielectric inclusion of cellulose nanoparticles (CNP), the present study provides experimental results for investigating anomalous switching properties via analyzing the features of dielectric (P-E) hysteresis loops. Different dielectric content of CNP (5, 15, 30, 50, 70 wt.%) was chosen. The P-E loops were measured at temperatures placed at the same distances from the phase transition point for all compositions. Besides, the influence of humidity (RH = 30, 60, 80, 100 %) was also investigated. It was clarified that the increase in cellulose content and relative humidity caused the increase in coercive field, accompanying the transformation of hysteresis loops from saturated into unsaturated ones. The nature of these anomalies was proposed to be associated with the role of hydrogen bonds in the composite.

Magnetic ordering induced magnetodielectric effect in Ho2Cu2O5 and Yb2Cu2O5

Materials with strongly coupled magnetic and electronic degrees of freedom provide new possibilities for practical applications. In this paper, we have investigated the structure, magnetic property, and magnetodielectric (MD) effect in Ho2Cu2O5 and Yb2Cu2O5 polycrystalline samples, which possess a non-centrosymmetric polar structure with space group Pna21. In Ho2Cu2O5, Ho3+ and Cu2+ sublattices order simultaneously, exhibiting a typical paramagnetic to antiferromagnetic transition at 13.1 K. While for Yb2Cu2O5, two magnetic transitions which originate from the orderings of Yb3+ (7.8 K) and Cu2+ (13.5 K) sublattices are observed. A magnetic field induced metamagnetic transition is obtained in these two cuprates below Néel temperature (T N). By means of dielectric measurement, distinct MD effect is demonstrated by the dielectric anomaly at T N. Meanwhile, the MD effect is found to be directly related to the metamagnetic transition. Due to the specific spin configuration and different spin evolution in the magnetic field, a positive MD effect is formed in Ho2Cu2O5, and a negative one is observed in Yb2Cu2O5. The spontaneous dielectric anomaly at T N is regarded as arising from the shifts in optical phonon frequencies, and the magnetoelectric coupling is used to interpret the magnetic field induced MD effect. Moreover, an H–T phase diagram is constructed for Ho2Cu2O5 and Yb2Cu2O5 based on the results of isothermal magnetic and dielectric hysteresis loops.

Investigations on dielectric relaxations, memory and thermistor applications in a liquid crystal nematogen

ABSTRACT A hydrogen bond liquid crystal comprising of 4-butyl benzoic acid and octyloxy benzoic acid is synthesised by well-documented methods which exhibits nematic phase with a wide thermal range. The aim of the present investigation is to investigate the aptness of the synthesised liquid crystal for applicational perspectives. Using this nematic liquid crystal, characteristics of thermistor and memory storage claims are demonstrated. The dielectric hysteresis loop is studied with respect to temperature, frequency and applied field. On the academic front, dielectric relaxations in nematic phase are extensively studied. Arrhenius plots are constructed and the activation energy (eV) is elucidated. Further, the growth order of the nematic phase is also estimated from the dielectric studies.

Electrophysical features of the hard ferroelectric material PKP-35

In this work, electrophysical features of the hard ferroelectric material PKP-35 are studied in a wide temperature range. Research object is a solid solution of lead zirconate-titanate (PZT) modified with some additives prepared by the conventional solid-state sintering method. The temperature dependences of the dielectric permittivity and dielectric losses in weak fields at frequencies of 1, 10, and 1000 Hz are obtained. The dielectric hysteresis loops at different temperatures are studied, the material features are revealed, the scope of application is determined.

Polarization properties of sodium-calcium niobate ceramics

The paper presents the results of studying the polarization properties of solid solutions ceramics, including sodium and calcium niobates at room temperature and frequency f = 50 Hz. Three classification regions of the dielectric hysteresis loops formation were identified. The nature of observed effects formations was determined.

Ferroelectric Switching and Phase Transition in Composites from Ferroelectric Metal–Organic Framework of [ND4][Zn(DCOO)3] and Silicon Dioxides

A composite from a ferroelectric metal–organic framework of [ND4][Zn(DCOO)3] and nano-dispersed silicon dioxides nanoparticles (nSiO2) has been synthesized. The study investigates the influence of nSiO2 on ferroelectric switching and phase transition properties in [ND4][Zn(DCOO)3]. It was indicated that the addition of nSiO2 led to the increase in phase transition temperatures and the inhibition of repolarization in ferroelectric parts. When the nSiO2 amount increased, the saturated dielectric hysteresis loops were more difficult to obtain and transformed into unsaturated ones with the rise of coercive field. The residual water molecules kept on nSiO2 were found to be responsible for the above anomalies.