Range Of Electric Fields Research Articles

In situ TEM measurement of electrical properties of individual BaTiO3 nanocubes

We report on the measurement of the electrical properties of individual pristine and doped BaTiO3 nanocubes by using in situ transmission electron microscopy with a two-electrode configuration. The dimensions of the nanocubes tested are between 10 and 20 nm, which rendered their in situ electrical characterization challenging. We characterized 4%Cr and 5%La (atomic percentage) doped BaTiO3 nanocubes and compared them with the properties of pristine BaTiO3 nanocubes synthesized by the same solvothermal method. We found that the resistance of all three types of nanocubes when displayed in log-scale shows a nearly linear dependence on the applied electric field (R2 ≥ 0.95) over a wide range of electric fields (50–900 kV/cm). Compared with pristine BaTiO3 nanocubes, the resistance of both 4%Cr and 5%La doped nanocubes showed reduced variation rates with respect to the electric field, with 5%La doping, demonstrating a better reduction in the variation rate. By developing techniques capable of evaluating the properties of individual BaTiO3 nanocubes, we expect that our work to open the door to the use of BaTiO3 nanomaterials in the design of future multilayer ceramic capacitors with improved volumetric efficiency and ferroelectrics-enabled nanodevices with advanced functionality.

Characteristics of current injection in the narrow-band p-CuTlS single crystal

The volt-amperage characteristics (VAC) and electrical conductivity of p-CuTlS single crystal have been investigated in a wide range of electric fields at 100 ÷ 300 K temperature range. It has been determined that in a narrow-band (Eg = 0.32 eV) CuTlS crystal, the current in an electric field of 10 40 V/cm, an increase in current is observed in consequence of ionization of local levels.

Capture and separation of CO2 on BC3 nanosheets: A DFT study

In order to reduce the greenhouse effect caused by the rapid increase of CO2 concentration in the atmosphere, it is necessary to develop more efficient, controllable, and highly sensitive adsorbing materials. In this study, the adsorption behavior of CO2 on BC3 nanosheets under an external electric field was explored based on density functional theory (DFT). It was found that CO2 experienced a transition from physisorption to chemisorption in the electric field range of 0.0060-0.0065 a.u.. In addition, the adsorption/desorption of CO2 is reversible and can be precisely controlled by switching on/off at the electric field of 0.0065 a.u.. The selective adsorption of CO2/H2/CH4 by BC3 can also be used to realize gas separation and purification under different electric fields. This study highlighted the potential application of BC3 nanosheets as a high-performance, controllable material for CO2 capture, regeneration, and separation in an electric field.

Is Chitosan the Promising Candidate for Filler in Nature-Friendly Electrorheological Fluids?

In this study, an electrorheological effect of the suspensions containing porous chitosan particles in olive oil in a wide range of electric fields is reported. Porous chitosan particles were produ...

An improved set of electron-THFA cross sections refined through a neural network-based analysis of swarm data.

We review experimental and theoretical cross sections for electron transport in α-tetrahydrofurfuryl alcohol (THFA) and, in doing so, propose a plausible complete set. To assess the accuracy and self-consistency of our proposed set, we use the pulsed-Townsend technique to measure drift velocities, longitudinal diffusion coefficients, and effective Townsend first ionization coefficients for electron swarms in admixtures of THFA in argon, across a range of density-reduced electric fields from 1 to 450 Td. These measurements are then compared to simulated values derived from our proposed set using a multi-term solution of Boltzmann's equation. We observe discrepancies between the simulation and experiment, which we attempt to address by employing a neural network model that is trained to solve the inverse swarm problem of unfolding the cross sections underpinning our experimental swarm measurements. What results from our neural network-based analysis is a refined set of electron-THFA cross sections, which we confirm is of higher consistency with our swarm measurements than that which we initially proposed. We also use our database to calculate electron transport coefficients in pure THFA across a range of reduced electric fields from 0.001 to 10 000 Td.

Mean-field simulation of hopping resistivity in a model with Coulomb interactions and current correlations

Simulations of hopping resistivity by mean-field methods rely on randomly generated site energies. Thus such effects as the presence of the Coulomb gap and electron current correlations have been simulated using predominantly Monte Carlo methods. This paper presents a method of mean-field calculation of hopping resistivity in a wide range of temperatures and electric fields. This method considers the long-range Coulomb interactions and at least partially accounts for the electron current correlations. Resulting curves reproduce the Mott law in the form predicted by Efros and Shklovskii and the experimentally observed electric field dependencies. Based on the results, a decrease of hopping energy is predicted with increasing temperature in the nearest-neighbor hopping regime. The report analyses the differences between the mean-field and the Monte Carlo approaches.

Electrostatic Modulation of Signaling at the Membrane Waveform- and Time-Dependent Electric Control of ERK Dynamics

The dynamics of extracellular-signal-regulated kinase (ERK) signaling regulates a wide variety of stimulated cellular processes and plays an important role in cell survival, motility, differentiation and proliferation. Here we show that a new range of alternative current electric field (AC EF) in the tens of KHz could non-invasively activate EGFR-Ras-ERK signaling pathway with precise timing and single-cell resolution, where electroporation or Faradaic processes have been deliberately avoided by using high-k dielectric passivated microelectrodes.

Modeling of charge effects in dielectric films of radiation MOS sensors

We have modeled the charge effects in radiation metal-oxide-semiconductor (MOS) sensors functioning in a wide range of electric fields including high-field injection of electrons into the dielectric film. In order to study the charge effects taking place in MOS sensors, we use the extended model suggested by us previously. The extended model, besides the accumulation of positive charge in the dielectric and the generation of the surface states at the interface, takes into consideration the accumulation of negative charge in the bulk of dielectric film caused by the electron capturing on traps. We demonstrate that the accumulation of the negative and positive charges in the bulk of the gate dielectric under high fields can significantly influence on the redistribution of electric fields inside the dielectric and, as a sequence, on change of the charge state of MOS structure which describes the sensor characteristics. We have ascertained that in order to properly utilize MOS sensors under high-field injection of electrons it has been necessary to take into consideration the possible capturing of electrons in the bulk of gate dielectric and adjust results of measurements with the model suggested.

Oxidative Effects during Irreversible Electroporation of Melanoma Cells-In Vitro Study.

Irreversible electroporation (IRE) is today used as an alternative to surgery for the excision of cancer lesions. This study aimed to investigate the oxidative and cytotoxic effects the cells undergo during irreversible electroporation using IRE protocols. To do so, we used IRE-inducing pulsed electric fields (PEFs) (eight pulses of 0.1 ms duration and 2–4 kV/cm intensity) and compared their effects to those of PEFs of intensities below the electroporation threshold (eight pulses, 0.1 ms, 0.2–0.4 kV/cm) and the PEFs involving elongated pulses (eight pulses, 10 ms, 0.2–0.4 kV/cm). Next, to follow the morphology of the melanoma cell membranes after treatment with the PEFs, we analyzed the permeability and integrity of their membranes and analyzed the radical oxygen species (ROS) bursts and the membrane lipids’ oxidation. Our data showed that IRE-induced high cytotoxic effect is associated both with irreversible cell membrane disruption and ROS-associated oxidation, which is occurrent also in the low electric field range. It was shown that the viability of melanoma cells characterized by similar ROS content and lipid membrane oxidation after PEF treatment depends on the integrity of the membrane system. Namely, when the effects of the PEF on the membrane are reversible, aside from the high level of ROS and membrane oxidation, the cell does not undergo cell death.

Investigation of structural, dielectric, and magnetoelectric properties of K0.5Na0.5NbO3–MnFe2O4 lead free composite system

In the present work, lead-free magnetoelectric composites (1 ̶x)K0.5Na0.5NbO3–(x)MnFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) synthesized by solid-state reaction route have been studied for their structural, dielectric, and magnetoelectric properties. The micro-structural analysis (XRD, FESEM, EDX, FTIR, and RAMAN spectroscopy) indicates the coexistence of diphase in the composites. Compared to the individual phases, composites exhibit better electrical properties such as low leakage current, high resistivity, high dielectric constant, and low dielectric loss. I–V characteristics reveal that the conduction behavior of the composites is ohmic in nature in whole tested electric field range at room temperature. The maximum value of dielectric constant is noticed for composite with 20 wt% of MnFe2O4 among the composites. The complex modulus analysis reveals the presence of non-Debye type phenomenon with spreading of relaxation time in the composites. Nyquist plots reveal that the composites exhibit polydispersive Maxwell–Wagner relaxation. The magnetic measurements indicate that the magnetic behavior of the composites lies on the mass content of MnFe2O4 phase. The magnetization increases with MnFe2O4 weight percentage which provides information regarding the magnetoelectric effect (ME) coupling between the magnetostrictive ferromagnetic and ferroelectric phases. Furthermore, ME effect is evaluated as a function of applied magnetic field. The highest ME response of 2.02 mV/cm-Oe is observed for composite with 80 wt% content of MnFe2O4. Findings of this research make these composites worthy material for environment-friendly ME device applications.

57Fe Mossbauer and electrical studies of Mn doped YFeO3 prepared via sol-gel technique

Polycrystalline YFe1−xMnxO3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) samples are prepared via sol-gel method. Structural characterization of these samples is done by x-ray diffraction (XRD) technique and Raman spectroscopic method. Intense peaks in XRD graphs show that the sample is crystalline in nature and Reitveld refined XRD data shows that the samples are formed in single phase. Raman spectroscopic study confirms the structure and phase purity of the samples. Room temperature 57Fe Mossbauer studies confirm that Fe ion exists in ferric state. The hyperfine field (Bhf) values are found to decrease with increase in manganese (Mn) concentration. This decrease in Bhf value indicates the increase in antiferromagnetic nature of the samples, which arises due to the weakening of magnetic interactions between the Fe ions. From room temperature leakage current density (J-E) measurements, it is observed that leakage current density increases with increase in Mn doping. Scanning electron micrographs explain the reason of increase in leakage current density based on the micro structure of the samples. The samples are found to exhibit Ohmic conduction mechanism in entire electric field range.

Deposition-temperature dependence of structure, ferroelectric property and conduction mechanism of BCZT epitaxial films

Ba0·85Ca0·15Zr0·1Ti0·9O3 (BCZT) epitaxial films were successfully deposited on (001) Nb-doped SrTiO3 substrate, and the effects of deposition temperatures on the structure, ferroelectric property, and conduction mechanism were studied. The results of XRD and AFM verified the well epitaxial structure with smooth surfaces of the deposited BCZT epitaxial films. BCZT epitaxial films deposited at 650 °C exhibited the best ferroelectric property (2Pr = 22.91 μC/cm2, 2EC = 1702.11 kV/cm) and relatively low leakage current density (7.91 × 103 A/cm2). The conduction mechanism of BCZT films corresponds to the space-charge-limited current (SCLC) mechanism and the Fowler-Nordheim (F–N) tunneling mechanism in the low and high electric field range, respectively.

FUNDAMENTAL STUDIES OF STEVIA REBAUDIANA BERTONI ON BREAST CANCER CELL COMBINED WITH LOW VOLTAGE PULSED ELECTRIC FIELD

Plant extract has found to be an effective and useful chemo preventive agents in various type of cancer. Plants extracts part, that most includes fruits, vegetable and spies. This extract can be used to prevent inflammation, wounds and infection. And recently, bioactive regent has shown to display anti-microbial, anti-oxidant, anti-inflammatory and anti-cancer properties. For this study, the chosen plant extract was Stevia rebaudiana Bertoni. It has known to be an effective treatment for allergies, treating cancer and cholesterol. While pulsed electric field has known to be an effective way to influence an opening pore on the cell membrane. It also had been used as one of the cancer treatment method in clinical practice nowadays. But, if these two methods combined, it might enhance more reduction in time taken for the cancer treatment process and less harmful/after side effect to the cancer patients. The most used range of pulse electric field are 1 – 1000 V/cm. the concentration will be known by finding the IC50 of stevia on breast cancer cell. The effectiveness of these method will be known by monitoring the cell proliferation, viability and antiproliferation of cancer cell. These methods might be an effective way to treat cancer without harming or left any after side effect to the cancer patients.

A preliminary study on mist CVD-derived ferroelectric Hf1−xZrxO2 films featuring its possibility of suitable operation for non-volatile analog memory

We have newly developed mist CVD-derived Hf1−xZrxO2 films and investigated their physical properties and basic electrical properties for application to ferroelectric analog memory device such as synaptic device for neuromorphic system. It is observed that the films consisted of microcrystal grain including ferroelectric orthorhombic phase by AFM and GIXRD measurements. Both HfO2 and ZrO2 film with 20 nm thickness showed good fatigue endurance against 109 counts of imposed pulse cycling, where some wakeup phenomena were observed. For a range of electric field (up to 1.5 MV cm−1) as memory-writing input with condition of minor ferroelectric hysteresis loop, a linear relationship between the input and resultant polarization at zero electric field, P(E = 0), was obtained. Finally, it is suggested that those films of HfO2, Hf0.55Zr0.45O2 and ZrO2 are basically applicable for the ferroelectric analog memory device. Further investigation is needed in view of degradation against the input electric field and imposed fatigue pulse.

Electric-field-induced structural changes for cubic system of lead-free and lead-based perovskite-type oxides

Changes in crystal structures of lead-free BaTiO3 (BT) and lead-based 0.70Pb(Mg1/3Nb2/3)–0.30PbTiO3 (PMN–PT) single crystals with a perovskite-type structure have been investigated under applied electric field by analyzing the high-energy synchrotron radiation X-ray diffraction data. The experiment is performed within the cubic phase in the phase diagram with the range of temperatures and electric fields where no electric field-induced phase transition is caused. The crystal structure analysis demonstrates that the crystal system is change to a tetragonal system by electrostriction when the electric field is applied along the crystal axis. The atomic arrangement in BT corresponds to the displacement pattern attributed to the Slater mode where Ti and O ions are mutually shifted in the opposite directions along the electric field, while that in PMN–PT is of the Last mode where Pb ions and (Mg, Nb)O6 oxygen octahedra are mutually shifted. The electron charge density study demonstrates that the Ba–O bonding in BT is ionic, whereas the Pb–O bonding in PMN–PT is highly covalent in the cubic structure. PMN–PT is revealed to have a characteristic Pb–O covalent bond which induces the atomic displacement attributed to the Last mode under applied electric field within the cubic phase despite no phase transition.

A continuum study of ionic layer analysis for single species ion transport in coaxial carbon nanotubes

In this letter, we employ the Poisson-Nernst-Planck equation and the continuum molecular model to investigate the ionic layers formation in coaxial carbon nanotubes, which are crucial for understanding the ion transport in nanomaterials, as well as modern solar cells and batteries. Owing to the curvature of nanotubes and the strong ion-nanotubes interactions, our simulations show that stable ionic multi-layers can always be formed inside nanotubes under a wide range of external electric fields and operating temperatures. Approximate solutions have also been deduced to support our numerical results. Most importantly, our hybrid model enjoys rapid and efficient computational times and hence fluid flow, conductivity and VI curve can be extracted almost instantaneously, which opens up a new research direction for the ion transport in nanomaterials.

Monte Carlo study of noise velocity fluctuations and microscopic carrier transport in monolayer transition metal dichalcogenides

The microscopic transport properties of electrons and holes in MoS2, MoSe2, WS2 and WSe2 are studied by means of an ensemble Monte Carlo simulator. Moreover, instantaneous carrier velocity fluctuations are analyzed in depth from a microscopic point of view, including their power spectral density, which is directly related to thermal noise in the GHz range. Results show important differences in the mean free path and momentum relaxation time for electrons and holes: valence band transport has, in general, a more ballistic character, particularly for tungsten based transition metal dichalcogenides. Electrons (especially in MoSe2 and WSe2) have faster momentum relaxation times in the whole electric field range under study. Transport in subsidiary valleys is relevant for electrons, while in the case of holes it only has a minor influence, being noteworthy only for WS2 at high electric fields. Holes present larger decay times of the velocity fluctuations correlation function: the faster decorrelation in the conduction band is associated to a larger scattering activity, a general trend observed in all the materials under study. The results indicate that it is to be expected a much larger thermal noise for p-type devices in the GHz range as compared to n-type devices: materials containing selenium have reduced levels of noise generated by velocity fluctuations, especially for electrons.

Measurement of the scintillation and ionization response of liquid xenon at MeV energies in the EXO-200 experiment

Liquid xenon (LXe) is employed in a number of current and future detectors for rare event searches. We use the EXO-200 experimental data to measure the absolute scintillation and ionization yields generated by $\gamma$ interactions from $^{228}$Th (2615~keV), $^{226}$Ra (1764~keV) and $^{60}$Co (1332~keV and 1173~keV) calibration sources, over a range of electric fields. The $W$-value that defines the recombination-independent energy scale is measured to be $11.5~\pm~0.5$~(syst.)~$\pm~0.1$~(stat.) eV. These data are also used to measure the recombination fluctuations in the number of electrons and photons produced by the calibration sources at the MeV-scale, which deviate from extrapolations of lower-energy data. Additionally, a semi-empirical model for the energy resolution of the detector is developed, which is used to constrain the recombination efficiency, i.e., the fraction of recombined electrons that result in the emission of a detectable photon. Detailed measurements of the absolute charge and light yields for MeV-scale electron recoils are important for predicting the performance of future neutrinoless double beta decay detectors.

The charge transport mechanism in amorphous boron nitride

The charge transport mechanism in thick film (~ 100 nm) amorphous boron nitride (a-BN) was studied experimentally and theoretically. Applying the experiments on the injection of minor carriers of n- and p-type silicon, the contribution of electrons and holes to the a-BN conductivity in the Si/BN/Al structure was determined. It was established that electrons and holes contribute to the a-BN conductivity, i.e. the a-BN conductivity is two-band. In a broad range of electric fields and temperatures, the charge transport in a-BN is satisfactorily described in the framework of the multiphonon trap ionization theory with thermal WT = 1.0 eV and optical Wopt = 2.0 eV trap ionization energies, respectively.

Origin of high electromechanical properties in (K,Na)NbO3 -based lead-free piezoelectrics modified with BaZrO3

After two decades of extensive research, selected lead-free piezoelectric materials based on the $(\mathrm{K},\mathrm{Na})\mathrm{Nb}{\mathrm{O}}_{3}$ (KNN) system exhibit excellent electromechanical properties that are comparable or even superior to those of $\mathrm{Pb}(\mathrm{Zr},\mathrm{Ti}){\mathrm{O}}_{3}$. The origin of the superior properties, however, remains insufficiently understood. Here, we establish a correlation between electromechanical properties and domain-wall dynamics for a prominent piezoceramic $(\mathrm{K},\mathrm{Na})\mathrm{Nb}{\mathrm{O}}_{3}$-based composition, modified with $(\mathrm{B}{\mathrm{i}}_{0.5}\mathrm{L}{\mathrm{i}}_{0.5})\mathrm{Ti}{\mathrm{O}}_{3}$ and different amounts of $\mathrm{BaZr}{\mathrm{O}}_{3}$. This composition combines excellent piezoelectric properties, high fatigue resistance, and low leakage currents. Domain-wall dynamics were studied over a broad range of electric fields, combining subcoercive field and dynamic pulse measurements. We find that the enhanced electromechanical properties in these materials are caused by easier domain-wall movement. Besides providing insights into fundamental mechanisms of domain-wall dynamics in KNN-based materials, our results can serve as a future guidance for the design of high-performance KNN compositions.