Maximum Polarization Value Research Articles

Electrical performance of organic molecule stabilized ultrafine tin(II) iodide particles: Towards an in-situ sensing application

The ultrafine monoclinic tin (II) iodide nanoparticles were synthesized using an organic–inorganic complexation method. The maximum value of dielectric constant (ε′) ∼ 94 was achieved at 80 °C under the frequency of 100 Hz. The device exhibited dipolar type of interaction in tin iodide system under the applied field condition and a maximum polarization value ∼ 0.34 μC/cm2 was obtained at 7.0 kV/mm. The polarization, dielectric and conductivity behaviour of tin iodide were also studied during the reaction between tin (II)-complex and potassium iodide. The method has the potential for future sensor applications.

Tuning of the ferroelectric and optical properties of ZnSnO3 with transition metals: Mn, Cr and Co

Using an approach based on the density functional theory, the electronic, polarization, structural, and optical properties of Co, Cr and Mn doped ZnSnO3 were studied. The analysis of the structural properties shows that the introduction of magnetic ions produces antiparallel magnetic states and reduces the band gap as compared with the gap of pristine ZnSnO3. Additionally, the results reveal the persistence of polarization after doping, reaching a maximum polarization value of 44.94 μC/cm2 for 12.5 % Co-doped ZnSnO3. These results highlight the importance of ZnSnO3 as a candidate material for solar energy harvesting, by combining a reduced gap and significant spontaneous polarization.

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.

Moderation of [Bi3+/Na1+] molar ratio for enhancement of dielectric and energy storage properties of NaNbO3 ceramics

Lead-free (Na1−3xBix)(Nb0.75Ti0.25)O3 (x = 0.0, 0.05, 0.1, 0.125 and 0.15) (NN-BT) ceramics were synthesized using solid-state reaction technique. The effect of Bi3+ into the crystal structure, dielectric, ferroelectric and energy storage properties of NNT ceramics were investigated. Pure NNT shows present perovskite structure with orthorhombic crystal structure at x ≤ 0.125, while Na3NbO8-NaNbO3 composite phase has been detected at x = 0.15. The tolerance factor (τ) decreased from 0.97 (x = 0.0) to 0.82 (0.15) which signified the composition deviated from perovskite structure at 0.15. Significant enhancement of dielectric constant at room temperature has been achieved by increasing Bi-content and the maximum value (∼1500) obtained at 0.1. The largest value of maximum polarization (Pmax) and smallest value of remnant polarization (Pr) were achieved at x = 0.1 due to orthorhombic NaNbO3 and rhombohedral (Na0.5Bi0.5)TiO3 coexistence phases. The substitution of monovalent (Na1+) by trivalent (Bi3+) lead to create sodium vacancies into the A-sites of NNT lattice subsequently increased the cations disorder and charge misfit. The maximum recoverable energy storage density (Wrec = 17.5 J cm−3) and energy storage efficiency (η = 80%) were achieved at x = 0.1, E ∼ 700 kV cm−1. Partially, (NNTB0.1) exhibit an outstanding stability of energy storage properties in terms of temperature range (25 to 150 °C) and frequency stability (2–20Hz). The present results imply the moderation ratio of Bi/Na plays an important role for enhancement of energy storage properties of NaNbO3 anti-ferroelectric ceramics.

Exploration of temperature driven conduction process and ferroelectric properties of Mn doped GdCrO3

This work delivers the research findings of the temperature dependent DC resistivity, AC impedance and ferroelectric polarization of GdCr1−xMnxO3 (x = 0 and 0.3). Mixed valence states of Cr (Cr3+ and Cr4+) are explored using the x-ray photoelectron spectroscopy analysis. The exponential decay of DC resistivity on escalating the temperature advocates the semiconducting-like nature for the probed samples. The DC resistivity data of these samples fit well into small-polaron hopping and variable range hopping models. The impedance attributes of these samples were scrutinized over a broad spectrum of temperatures at selected frequencies. The values of the real and imaginary parts of impedance unveil substantial reduction on raising the temperature, thereby signifying the increase in conductivity of the samples. Pristine sample displays an electrical relaxation peak at 65 °C, which translates towards the lower temperature at higher frequencies. Further, the semicircular behavior of Nyquist plots at higher temperatures indicates the reduction of the charge transfer resistance. The equivalent circuits of Nyquist plots are generated using Z-view software. From these plots, it is perceived that grain boundary resistance upsurges while the grain resistance and capacitance drops upon doping. The ferroelectric measurements reveal that the coercive field (Ec) values decrease whereas the values of maximum polarization (Pm), remnant polarization (Pr) and energy storage increase in 30% doped GdCrO3. These observations establish that electrical and ferroelectric properties of GdCrO3 system can be tuned with appropriate Mn doping.

Electrophysical Properties of PZT-Type Ceramics Obtained by Two Sintering Methods

This study demonstrates the impact of two sintering techniques on the fundamental properties of doped PZT-type ceramic materials (with Mn4+, Sb3+, Gd3+, and W6+), with the general chemical formula Pb(Zr0.49Ti0.51)0.94Mn0.021Sb0.016Gd0.012W0.012O3. The synthesis of ceramic powders was carried out through the calcination method. Two different methods were used in the final sintering process: (i) pressureless sintering (PS) and (ii) hot pressing (HP). The PZT-type ceramics were subjected to electrophysical measurements, encompassing various analyses such as X-ray diffraction (XRD), microstructure (scanning electron microscopy (SEM)), ferroelectric and dielectric properties, and DC electrical conductivity. The analysis of the crystal structure at room temperature showed that the material belongs to the perovskite structure from the tetragonal phase (P4mm space group) without foreign phases. Both sintering methods ensure obtaining the material with appropriate dielectric and ferroelectric parameters, and the tests carried out verified that the ceramic materials have a diverse range of parameters appropriate for use in micromechatronic and microelectronic applications. The obtained ceramic material has high permittivity values, low dielectric loss tangent values, and high resistance. At room temperature, the ceramic samples’ P-E hysteresis loops do not saturate at a field of 3.5 kV/mm (Pm maximum polarization is in the range from 12.24 to 13.47 μC/cm2). However, at higher temperatures, the P-E hysteresis loops become highly saturated, and, at 110 °C, the Pm maximum polarization values are in the range from 28.02 to 30.83 μC/cm2.

Achieving large energy density and high efficiency in (Bi0.5Na0.5)0.7Sr0.3TiO3–Ba(Mg1/3Sb2/3)O3 ceramic

Recently, due to ultra-high energy density and exceptionally fast discharge time, high-performance dielectric capacitors have become a research hotspot in electric pulse power equipment. However, it is challenging to achieve a hige energy storage density and efficiency of ceramic worked in the area for capacitors. Herein, novel (1-x) (Bi0.5Na0.5)0.7Sr0.3TiO3-xBa(Mg1/3Sb2/3)O3 (xBMS, x = 0.08, x = 0.10, x = 0.12, x = 0.14) dielectric ceramics were prepared by a solid state reaction method. 0.10BMS ceramic has a large maximum polarization value of 37.1 μC/cm2 at 330 kV/cm, which achieves a high energy storage density of 4.42 J/cm3 and ultra-high efficiency of 93 %. Meanwhile, 0.10BMS ceramic has great energy storagy stability in the temperature range of 40–140 °C and the frequency range of 4–200 Hz. In addition, the sample also shows an fast t0.9 of 60.8 ns, high CD of 806.8 A cm−2, and PD of 48.41 MW/cm3. Therefore, 0.10BMS ceramic has potential application prospects in electronic devices.

Temperature and frequency dependent dielectric capacitance and polarization performances of low dimensional perovskite based manganese stannate

Manganese stannate perovskite nanoparticles were synthesized by applying a complexation mediated approach. Rietveld refinement of the XRD data exhibited orthorhombic structure with space group of Pnma. The structure included eightfold coordinated Mn2+ cation, surrounded by eight O2− anions and formed MnO8 polyhedra unit. Each polyhedra unit interconnected through the corner-sharing SnO6 octahedra with the formation of a cage-like network. The temperature and frequency dependent dielectric performances of manganese stannate were measured in the form of a device, which exhibited maximum dielectric constant value ~ 3445. The high dielectric constant value was originated due to the contribution of space charge polarization and orientation polarization of dipoles within the measured frequency ranges. Temperature and frequency dependent AC-conduction mechanism of the manganese stannate-based device involved both overlapping large polarons and non-overlapping small polarons. Electric field-dependent of polarization hysteresis loop of the device exhibited the maximum polarization value 1.5 µC/cm2 under the electric field of 3 kV/mm. Under the applied field of 2 kV/mm, the device exhibited a fatigue-free polarization with a maximum value of 0.92 µC/cm2, sustained for 103 cycles under ambient temperature condition.

Improvement of the energy storage performance in Pb0.88La0.12ZrO3 thin films by inserting ZrO2 layer

A method for significantly enhancing the breakdown field strength and energy storage density of Pb0.88La0.12ZrO3 (PLZ) films by inserting ZrO2 (ZO) layer is provided. PLZ films with the inserting layer of ZrO2 were deposited on SiO2/Si substrates buffered with LaNiO3 films by the sol-gel method. The effect of ZrO2 precursor solution concentration on structure and electrical properties was investigated. The results show that for the composite films with the sandwich structure, much improved electrical breakdown strength values of 1543 kV/cm and maximum polarization values of 83.5 μC/cm2 were obtained, which are 141% and 40% higher than pure PLZ films, respectively. With the combination of a high breakdown field strength and a large maximum polarization value, the film has an energy storage density of up to 32.6 J/cm3 when ZrO2 precursor solution concentration is 0.1 mol/L. Our results show that the design of PLZ/ZO/PLZ composite films is an effective way to obtain high energy storage density capacitors.

Remarkably minimized domain and elevated energy storage properties in Na0.48Bi0.48Ba0.04TiO3-based relaxor antiferroelectrics by interposing Bi(Mg2/3Ta1/3)O3

Lead-free dielectric capacitors have been embraced recently due to their tiny volume, large energy density and superfast charge–discharge speed. Here, a recoverable energy storage density of ∼ 10.73 J cm−3 and an efficiency of ∼ 80.5% were simultaneously revealed in traditional sintering (1 − x) (Na0.48Bi0.48Ba0.04TiO3)-xBi(Mg2/3Ta1/3)O3 (x = 0.16) ceramics (BNBT-0.16BMT) under an applied electric field of 540 kV cm−1 via disordering B-site ions and modifying the B-site cation ratio. Specifically, the disorder of B-site ions was found to alter the crystal structure, delaying maximum polarization. Phase switching between rhombohedral and tetragonal was characterized with transmission electron microscopy, Raman scattering and dielectric constant curves. Mg/Ta dopant was shown to cause electric charge mismatch and change dielectric anomaly peaks, leading to a large maximum polarization value. Finally, BNBT-0.16BMT stabilizes the relaxor antiferroelectrics (RAFE) system, with a significant broad frequency (0.5–120 Hz), broad temperature stability (20–160 °C), and excellent discharge performance (WD ∼ 5.23 J cm−3; Ea ∼ 350 kV cm−1). This preparation shows potential for broad application in dielectric capacitors.

Transport and thermoelectric performance of Fluorine functionalized Ge-carbide sheets

Based on density functional theory simulations, GW approximation + BSE and the semi-classical Boltzmann transport theory, electronic ,optical and thermoelectric response of bidimensional fluorinated Ge-carbides are investigated. Three configurations are considered, namely F-CGe, CGe-F, F-CGe-F to explore the effect of both fluorination distribution and coverage. It is shown that the conduction (valence) band is shifted upwards (downwards) when F decorates C-atoms (Ge-atoms) which tunes the gap energy. Furthermore, full fluorination makes CGe sheet better dielectric structure. The maximum reflectivity and absorption reveal that F-CGe-F structure exhibits better optical response, unlike its two counterparts constrained to absorb incident photon energy to the UV region only. The maximum polarization values are found in the visible region for the half fluorinated structure F-CGe and in the UV spectrum for F-CGe-F and CGe-F. The Fluorination also improves the transport properties of CGe which significantly increases its merit factor (ZT) at room temperature. Th three compounds are found to exhibit an ultralow lattice conductivity which leads and a record high ZT up to 0.65, 0.77, and 0.81 at 900 K in CGe-F, F-CGe and F-CGe-F respectively. Our results evaluate the potential of fluorinated CGe sheets as suitable thermoelectric materials at the ambient temperature.

Structural, dielectric and ferroelectric properties of Ba(1-x)PbxTi(1-x)ZrxO3 ceramics

ABSTRACT Polycrystalline ceramic samples with compositional formula Ba(1-x)PbxTi(1-x) ZrxO3 (x = 0, 0.05, 0.075, 0.10, 0.15, 0.20) were prepared by the conventional solid-state reaction route (SSR). All the samples were sintered at 1300°C for 4 h in closed high-density alumina crucibles with the lead-rich environment. Sintered samples were subjected to X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) for structural analysis. XRD analysis confirmed tetragonal to orthorhombic phase transition for samples with x ≥ 0.10. The relative permittivity and loss were measured as a function of temperature at 1, 10, 100 and 1000 kHz frequencies. The value of relative permittivity at room temperature was found to be increased with an increase in x. PE hysteresis loops were recorded for all the samples (at 30°C and 50 Hz). It was found that the sample with x = 0.05 shows the maximum value of remanent polarization ‘Pr’ = 18.51 µC/cm2.

Dielectric capacitance and energy storage performances of organic molecule stabilized hexagonal lead iodide with a layered network

Nanostructured lead iodide particles were synthesized by applying a wet chemical synthesis route in presence of aminobenzene and fluoro-aminobenzene as ligands. The ligands were performed as the stabilizer of the particles. Two types of devices were designed using aminobenzene and fluoro-aminobenzene stabilized lead iodide. The dielectric capacitance, AC-conductivity, field-driven polarization and energy storage performances of the devices were investigated under varying temperature and frequency conditions. The electrical performance of fluoro-aminobenzene stabilized lead iodide-based device exhibited superior performance than that of aminobenzene-stabilized lead iodide-based devices. The fluoro-aminobenzene based device showed the maximum dielectric constant value 398 under the frequency of 100 Hz at 80 °C and maintained a low dielectric loss and high quality factor within the frequency range from 100 Hz to 2 kHz. Both the devices demonstrated the small polaron hopping conduction mechanism. The fluoro-aminobenzene based device maintained a fatigue-free unipolar hysteresis loop under 4 kV/mm with the maximum polarization value of 0.21 μC/cm2 and attended a stable charge and discharge energy density for the period of 103 cycles.

Polarization, polarizing efficiency, and grain alignment towards the direction of the cluster NGC 2345

ABSTRACT We have investigated the grain alignment and dust properties towards the direction of the cluster NGC 2345 using the multiband optical polarimetric observations. For the majority of the stars, the observed polarization is found to be due to the interstellar medium with average values of maximum polarization and wavelength corresponding to it as 1.55 per cent and 0.58 $\mu$m, respectively. This reveals a similar size distribution of dust grains to that in the general interstellar medium in the direction of NGC 2345. Alteration of dust properties near the distance of 1.2 kpc towards the direction of NGC 2345 has been noticed. The dust grains located beyond this distance are found to be aligned with the Galactic magnetic field, whereas a dispersion in the orientation of the dust grains lying in the foreground of this distance is found. Polarizing efficiency of grains in this direction is found to be close to the average efficiency for our Galaxy. The decreased grain size along with the increased polarizing efficiency towards the core region of the cluster indicates the local radiation field is higher within the cluster, which is responsible for the increased alignment efficiency of small grains. The wavelength of maximum polarization (associated with the average size of aligned grains) is also found to increase with extinction and reduces with the increase in polarizing efficiency, which can be explained by the radiative torque alignment mechanism.

Electrical response on the nickel-ion containing organic–inorganic hybrid system for the sensing of dopamine

A complexation mediated route has been applied for the synthesis of Ni(II)-HMDA (hexamethylenediamine) hybrid system and the synthesized complex material was tailored as a sensing platform of dopamine. The electric field induced polarization study exhibited the hysteresis loop for Ni(II)-HMDA and with the gradual addition of dopamine to the complex, a steady increase of maximum polarization value of the loop was noticed. The increment of the polarization hysteresis loops were associated with the ligand exchange mechanism between HMDA and dopamine. The dopamine sensing performance of Ni(II)-HMDA hybrid system was further studied using the dielectric capacitance, AC-conductivity measurement and impedimetric techniques.

Fabrication and dielectric performance of RGO-PANI reinforced PVDF/BaTiO3 composite for energy harvesting

Today’s techno savvy world demands smart devices which are light-weight, flexible, and scalable. Functional polymers and their composites are suitable candidates that can fulfill the requirements in flexible device applications. Polyvinylidene fluoride (PVDF) is one kind of functional polymers possessing a large dielectric strength as well as permanent electrical dipole. To improve the dielectric and ferroelectric performance of the PVDF polymer, it can be hybridized with an inorganic/organic inclusion phase, usually ferroelectric ceramic particles or nano-sized low dimensional carbon. In this work, reduced- graphene oxide (RGO) and RGO-PANI were chosen as the inclusion phase (filler). The present work focuses towards enhancing the dielectric and ferroelectric properties of PVDF-BaTiO3 (P/BT) nanocomposites impregnated with RGO and RGO/PANI(Polyaniline) nanofillers. In-situ polymerization method was adapted to fabricate the RGO/PANI nanocomposite and spin coating method for P/BT composites. X-ray diffractograms and FTIR corroborate the presence of ferroelectric phases in P/BT matrix. Wayne Kerr precision impedance analyzer was used in the frequency frame of 1 Hz to 1 MHz and temperature window from 30 °C to 160 °C to study the dielectric properties. The P-E hysteresis loops were obtained using Radiant Ferroelectric Tester at different voltage cycles. The dielectric constant of P/BT matrix with 0.03% RGO loading exhibited the highest dielectric constant 2 × 105. Remarkable increase in the energy density of composites with filler loading was observed. P/BT with 1 wt% loading of RGO-PANI achieved the maximum value of polarization 3.6 µC/cm2 and discharge energy density 0.76 J/cm3 (under the electric field of 170 kV/cm) with 55% efficiency. This contribution provides a potential route to design and fabricate high energy density flexible capacitor for microelectronic devices.

The electrocaloric effect of PBZ/PVDF flexible composite film near room temperature

Pb0.8Ba0.2ZrO3 (PBZ) nanofibers were prepared through electrospinning and mixed at a volume composite ratio of 0–6% with polyvinylidene fluoride (PVDF) dissolved in an organic solvent, and the PBZ/PVDF composite film was prepared through casting. The nanocomposites with PBZ nanofibers of 3 vol% showed the best ferroelectric performance in this work, and the maximum polarization value and breakdown field strength were 9.69 μC/cm2 and 420 MV/m, respectively. The dielectric constant and dielectric loss at a depolarization temperature of 285 K were 6.13 and 0.21, respectively. The performance of the electrocaloric effect was studied using the direct method near room temperature. Under 150 MV/m and − 30 °C, the △T and ΔS of the composite film were 13.99 K and 52.70 J/kg K, respectively. When the temperature increased to 70 °C, △T and ΔS become 5.08 K and 13.56 J/kg K, respectively. The simulation results and experiments indicate that the incorporation of nanofibers can increase the interface polarization with higher polarization value and improve the ferroelectric performance than pure PVDF.

Investigation on Multiferroic Properties and Conduction Mechanism in Cobalt Doped Bi0.9Nd0.1FeO3 Solid Solutions

Bi0.9Nd0. 1Fe1–x Co x O3 (x = 0.025, 0.050, 0.075 and 0.1) solid solutions have been synthesized by doping of Co3+ at the Fe3+ site using solid-state reaction method. The prepared solid solutions have been investigated for their structural, magnetic, ferroelectric and magneto-dielectric properties and conduction mechanism. The XRD study reveals that all the solid solutions possess a rhombohedral symmetry. The vibrating sample magnetometer study reveals that all the samples possess magnetic orders and the remnant magnetization has been found to be increased from 0.2388 emu/g for x = 0.025 to 0.7112 emu/g for x = 0.1. The non-Debye type dielectric relaxation has been investigated for all the samples. The frequency dependent ac conductivity data follows Jonscher’s Power law. Variation of exponent n versus temperature follows the overlapping large polaron tunneling conduction model. The maximum value of remanent polarization (∼0.152 μC/cm2) was found for x = 0.1. All the samples exhibit positive magneto-dielectric response in the low-frequency region with the highest magneto-capacitance value of 13.54% at 500 Hz for sample x = 0.1.

The effects of Sn substitution on the phase, microstructure, and dielectric properties of 0.94(Bi0.5Na0.5)TiO3–0.06Ba(Zr0.1Ti0.9)O3 ceramic system

0.94(Bi0.5Na0.5)TiO3–0.06Ba(Zr0.1Ti0.9-xSnx)O3 (x = 0, 0.08, 0.1) (BNT-BZST) ceramics were synthesized via conventional mix oxide sintering route. X-ray diffraction, scanning electron microscopy, inductance (L), capacitance (C), and resistance (R) (LCR) measurement meter, d33 meter, and ferroelectric testes system were used for determining the phase, microstructure, ferroelectric and piezoelectric properties of the samples. Dense microstructure with a decrease in the average grain size with an increase in Sn content was observed. Improvement in the ferroelectric and piezoelectric properties such as dielectric constant (εr), dielectric loss (tanδ), polarization (P), and piezoelectric coefficient (d33) was observed for 08 wt% of Sn substituted sample. A maximum values of saturated polarization (Pmax) ~ 55 µC/cm2, a remnant polarization (Pr) ~35 µC/cm2, d33~130 pC/N and εr ~3895 (1 MHz) at Tm~264 °C were obtained for x=0.08.

Microbial Inoculation for Productivity Improvements and Potential Biological Control in Sugar Beet Crops.

Used mainly for sucrose production, sugar beet is one of the most important crops in Castilla y León (Spain). Several studies have demonstrated the benefits of microorganisms in different crop management programs, among which Plant Growth Promoting Rhizobacteria (PGPR). This research aims to assess the beneficial effects of two PGPRs strains (Pseudomonas fluorescens Pf0-1 and Pseudomonas chlororaphis CECT 462) on sugar beet (Beta vulgaris) production. Three treatments: a PGPRs co-inoculation assay of untreated seeds without any chemical treatment (TB), a conventional treatment with commercial seeds and fungicide application (TT); and a control with seeds without protective coating, bacterial inoculation and chemical treatment (ST). The efficacy of PGPRs inoculation on sugar beet production was determined measuring periodically the photosynthetic status of plants, and the final yield and quality of tubers. Aerial and root plant biomass, maximum beet perimeter, polarization, and sugar values of the sugar beet plants inoculated with PGPRs showed higher values and significant differences to sugar beet subjected to other treatments. We could see that PGPRs inoculation (TB treatment) produced significant differences in the quantum yield of PSII (ΦPSII). TB showed the highest value for ΦPSII and the NPQ (non-photochemical quenching), the lowest value, even though the PSII (maximum quantum yield of photosystem II) was very similar in all treatments. The two assayed PGPR strains triggered a significant increase in sugar beet production yield and quality. PGPRs inoculation techniques could be used in different crops and they could be applied as biofertilizers, improving the agricultural production.