Field Dependence Of Polarization Research Articles

Eliminating Qubit-Type Cross-Talk in the omg Protocol.

The omg protocol is a promising paradigm that uses multiple, application-specific, qubit subspaces within the Hilbert space of each single atom during quantum information processing. A key assumption for omg operation is that a subspace can be accessed independently without deleterious effects on information stored in other subspaces. We find that intensity noise during laser-based quantum gates in one subspace can cause decoherence in other subspaces, potentially complicating omg operation. We show, however, that a magnetic-field-induced vector light shift can be used to eliminate this source of decoherence. As this technique simply requires choosing a specific, magnetic field-dependent polarization for the gate lasers, itis straightforward to implement and potentially helpful for omg-based quantum technology.

Studies on structural, dielectric, electrical, and ferroelectric properties of the polycrystalline: Sr3Bi2WO9

Today, great emphasis is placed on the creation of lead-free compounds that may be used in multi-functional equipment. This report describes the synthesis (through the solid-state technique) and physical characteristics (structural, electrical, and ferroelectric) of a polycrystalline Sr3Bi2WO9 compound (SBWO). A monoclinic crystal structure with cell parameters; a = 9.0285 Å, b = 16.6457 Å, c = 5.6787 Å with β = 93.13° is studied by analysis of X-ray diffraction method (crystallite size 100.77 nm). The purity, morphology, and elementary composition of elements were studied by SEM (grain size 0.582 μm) and EDX. The temperature-frequency variation of ε r, tan δ, and σ ac were investigated. The drop in grain resistance value with increasing temperature demonstrates the NTCR property of the compound. It has been reported that the conduction process of the compound is based on a study of the modulus spectrum. SBWO is a possible choice for devices because it exhibits outstanding temperature-independent ε r characteristics and reduced tanδ. Ferroelectric properties of the material (E c=0.2655 kV/cm, P r=0.00454 μC/cm2, E max=2.478 kV/cm, and P max=0.0367 μC/cm2) shown by the electric field-dependent polarization at 25 °C.

Low-dimensional lead chromate-based hybrid system for capacitance and polarization performances: a flexible device for pressure-induced voltage generator

AbstractOrganic molecule–functionalized lead chromate nanoparticle was synthesized using a complexation strategy route. The structural characterization revealed the single-phase lead chromate system belongs to monazite-type monoclinic structure with the space group of P21/n. The unit cell consists of an alternating chain of polyhedra (PbO9) and tetrahedra (CrO4) units, connected via edge and corner-sharing arrangement. A flexible device of lead chromate was fabricated and investigated dielectric capacitance, electrical impedance, conductivity, and field dependent polarization performances under different frequency and temperature environments. The device displayed a maximum dielectric constant (εʹ) value ~ 2400 at 120°C under 100 Hz frequency condition. High dielectric constant value is originated from the orientation polarization of CrO4 unit and space charge contribution in the system. AC conductivity of the device suggested the polaronic charge carriers control the overall conduction process via localized hopping mechanism. A fatigue-free polarization behavior was observed in the device under the applied field of 4.0 kV/mm, for 103 cycles and retained the polarization value ~ 0.26 μC/cm2 over the switching cycles. Lead chromate–based device also showed pressure-induced voltage generation under different pressure conditions and could have the potential application as a voltage generator.

Dielectric and piezoelectric properties of 0.8Na0.5Bi0.5TiO3-0.2BaTiO3 modified with sodium niobate

In this paper, we present the dielectric and piezoelectric properties of tetragonal 0.8Na0.5Bi0.5TiO3-0.2BaTiO3 modified with NaNbO3 ((1-x)[0.8Na0.5Bi0.5TiO3-0.2BaTiO3]-xNaNbO3). Our experimental study has revealed that the ferroelectric phase in these compositions is suppressed with the increase of sodium niobate concentration. A broad anomaly, resembling relaxor ferroelectrics, appears in the 325–450 K temperature interval. The investigation of the electric field dependence of polarization has indicated that the double hysteresis loop behaviour is characteristic of the modified compositions, which is associated with the 1st order phase transition under the applied electric field. The experiments below room temperature have revealed that the range of stability of the ferroelectric phase is shifted to lower temperatures upon the increase of sodium niobate concentration. The electromechanical displacement in the modified compositions shows a similar maximum displacement in the whole concentration range. The electromechanical response in 0.8Na0.5Bi0.5TiO3-0.2BaTiO3 solid solutions is due to the piezoelectric effect, while, in the mixed compositions, it is related to the jump-like change of the lattice constants in the vicinity of electric fieldinduced 1st order phase transition.

Organic molecule functionalized lead sulfide hybrid system for energy storage and field dependent polarization performances

A wet chemical route is reported for synthesising organic molecule stabilized lead sulfide nanoparticles. The dielectric capacitance, energy storage performances and field-driven polarization of the organic–inorganic hybrid system are investigated in the form of a device under varying temperature and frequency conditions. The structural analysis confirmed the formation of the monoclinic phase of lead sulfide within the organic network. The band structure of lead sulfide was obtained by density functional theory calculation that supported the semiconductor nature of the material with a direct band gap of 2.27 eV. The dielectric performance of the lead sulfide originated due to the dipolar and the space charge polarization. The energy storage ability of the material was investigated under DC-bias conditions, and the device exhibited the power density values 30 W/g and 340 W/g at 100 Hz and 10 kHz, respectively. The electric field-induced polarization study exhibited a fatigue-free behaviour of the device for 103 cycles with a stable dielectric strength. The study revealed that the lead sulfide-based system has potential in energy storage applications.

Electromechanical Properties of Modified BaTiO<sub>3</sub> Ceramics

The microstructure, energy dispersive X-ray spectra, and field dependent polarization and electrostrictive strain characteristics of x(Ba0.7Ca0.3)TiO3–(1-x)Ba (Zr0.2Ti0.8)O3; x = 0, 0.5, and 1.0 synthesised using solid-state reaction process are discussed in this work. The X-ray diffraction process and scanning electron microscope were, respectively taken into use to examine the forming of single-phase compound and the surface morphology as well as elemental analyses of all of the samples. The grains sizes were found to lie between 3–12 μm and was largest for x = 0.5. The value of piezoelectric coefficient, converse piezoelectric effect (strain maximum to peak electric field), and electrostrictive coefficient were found to be the highest for x = 0.5 sample. Ba0.85Ca0.15Zr0.10Ti0.90O3 was shown to be a potential lead-free electrostriction material for industrial applications, particularly in positioning actuators, based on field-dependent polarisation and strain experiments at ambient temperature.

Strain and electric field dependent spin polarization in two-dimensional arsenene/CrI3 heterostructure

Spin polarized van der Waals (vdW) heterostructures have attracted considerable interest owing to the spin splitting manipulation. In this paper, first-principles calculations are employed to explore the two-dimensional arsenene/CrI3 vdW heterostructure as a promising spin polarized material, as well as the spin polarization under strain and electronic field are investigated. The most stable stacking configuration and ferromagnetic (FM) property of the arsenene/CrI3 vdW heterostructure have been confirmed. The detailed calculations show that the Curie temperature (Tc) of the FM coupling CrI3 layer in the heterostructure can be enhanced up to 61 K, which is attributed to both superexchange interaction and proximity exchange effect. The electronic structures suggest that this heterostructure possess an intrinsic type-II band alignment and diluted magnetic semiconductor property. Interestingly, we found a transition from diluted magnetic semiconductor to half-metal and gradually to metal induced by the biaxial strains, and the extra electronic field can modulate the “maxican hat” of the valance band maximum (VBM) of arsenene. Our work provides not only application prospects of the arsenene/CrI3 vdW heterostructure nanodevices but also theoretical effective support for the research and development of the spin electronics and flexible electronics.

Multiferroic Properties of Pure and Ion‐Doped BiCrO3 Bulk and Thin Films

The multiferroic properties of BiCrO 3 (BCO) bulk and thin films are investigated for the first time using a microscopic model. The influence of ion doping on the multiferroic properties of BCO is also studied because the doping process changes the physical properties and can be used for potential applications in magnetoelectronic devices. The magnetization M increases by Mn and decreases by Ga-ion doping whereas the Néel temperature T N decreases in both cases. There are some discrepancies by polarization whether it is ferroelectric or antiferroelectric. It is shown that bulk pure BCO is antiferroelectric because the electric field dependence of polarization P shows a double hysteresis loop and the dielectric constant has no anomalies at T N . In Ga-, Mn- or Ti-doped BCO a ferroelectric polarization appears. The specific heat shows a peak at T N for BCO. By Ga doping, this peak vanishes with increasing x. The multiferroic behavior of BCO is demonstrated in the magnetic field dependence of the dielectric constant. In BCO thin films, ferroelectric and ferromagnetic behavior is observed.

Structural, dielectric, electrical and optical properties of a double perovskite: BaNaFeWO6 for some device applications

In this paper, the synthesis (by solid-state reaction route) and characterization (structural, microstructural, electrical, and optical properties) of the BaNaFeWO6 lead-free double perovskite are reported. Room temperature structural analysis suggests that the material crystallizes in monoclinic crystal symmetry with average crystallite size and lattice strain of 55 nm and 0.023% respectively. The incorporation of the Na/Fe at both sites (Ba and W) of BaWO4 is confirmed from the room temperature Raman study. A study of microstructural and compositional characteristics of the sample by using scanning electron microscopy (SEM) and EDAX (energy dispersive analysis X-ray) has provided the quality (uniform and compactness) of the sample. The detailed studies of the frequency and temperature dependence of dielectric, impedance, and conductivity properties of the material suggest the presence of high dielectric dispersion, non-Debye conduction, and relaxation mechanism in it. The semiconducting nature is confirmed by the decreasing resistance or radius of semicircular arcs in both impedance analysis and Nyquist plots. This nature is also well supported by fitted parameters evaluated using ZSIMPWIN software. The temperature dependence of resistance provides a good stability factor, sensitivity factor, and thermistor constant, which may be useful for applications in the fields of the thermistor-related devices. The field-dependent polarization (P-E) hysteresis loop suggests the possibility of ferroelectricity in the sample. The sample has an energy bandgap of 2.72 eV deduced from its UV–visible spectrum, which may be useful for some applications in optoelectronic devices

Nonmonotonic Magnetic Field Dependence of Remnant Ferroelectric Polarization in Reduced Graphene Oxide–BiFeO3 Nanocomposite

The thin‐film heterostructures or nanocomposites exhibit vastly different properties from those observed in bulk systems. Herein, in a nanocomposite of reduced graphene oxide (RGO) and BiFeO3 (BFO), the remnant ferroelectric polarization is found to follow nonmonotonic magnetic field dependence at room temperature as the applied magnetic field is swept across 0–20 kOe on a pristine sample. Bulk BiFeO3, in contrast, exhibits monotonic suppression of polarization under magnetic field. The remanent ferroelectric polarization, in the present case, is determined, primarily, from powder neutron diffraction patterns recorded under 0–20 kOe field. The nanosized (≈20 nm) particles of BFO are anchored onto the graphene sheets of RGO via FeC bonds with concomitant rise in covalency in the FeO bonds. Field‐dependent competition between positive and negative magnetoelectric coupling arising from magnetostriction due to, respectively, interface and bulk magnetization appears to have given rise to the observed nonmonotonic field dependence of polarization. The emergence of FeC bonds and consequent change in the magnetic and electronic structure of the interface region have influenced coupling between ferroelectric and magnetic properties remarkably and thus creates a new way of tuning the magnetoelectric properties via reconstruction of interfaces in nanocomposites or heterostructures of graphene/single‐phase‐multiferroic systems.

Dielectric, Magneto-Dielectric & Magnetic Properties of x[Co<sub>0.9</sub>Ni<sub>0.1</sub>Fe<sub>2</sub>O<sub>4</sub>]-(1-x)[0.5Ba<sub>0.7</sub>Ca<sub>0.3</sub>TiO<sub>3</sub>-0.5BaZr<sub>0.2</sub>Ti<sub>0.8</sub>O<sub>3</sub>] Multiferroic Composite

In the present work, we have synthesized x [Co0.9Ni0.1Fe2O4]-(1-x) [0.5Ba0.7Ca0.3TiO3-0.5BaZr0.2Ti0.8O3], x = 0.3, 0.4 & 0.5 multiferroic composite by hydroxide co-precipitation method. The structural and morphological analysis of the composite was carried out by using X-ray diffraction and Scanning Electron Microscopy. The XRD spectra confirm the perovskite phase and spinel phase. Dielectric properties of the composite were studied using Impedance analyzer. The variation of dielectric constant and loss of tangent (Quality factor) in the frequency range of 100 Hz to 1 MHz were investigated. Magnetocapacitance were measured for magnetic field up to 1 Tesla, which increases with increase in magnetic field. Dielectric constant possesses contribution due to magnetic field dependent interfacial polarization and variation due to induced stress which can be explained on the observed MD effect. Saturation magnetization of composites increases with increase in CNFO content.

Structural, microstructural and electrical characteristics of Ca, Sn and Se modified Bi0.5Na0.5TiO3 ferroelectric ceramics

In this paper, studies of structural, microstructural and electrical properties of calcium, tin, and selenium modified bismuth sodium titanate (Bi0.5Na0.5TiO3) compound with a general chemical formula (Bi0.45Na0.45Ca0.1) (Ti0.9Sn0.05 Se0.05) O3, synthesized by a high-temperature mixed oxide reaction method, have been discussed. Analysis of room temperature X-ray diffraction data confirms the formation of perovskite single-phase compound with rhombohedral symmetry. The surface morphology of the sample exhibits the uniform distribution of grains of varying size. Studies of the electrical parameters (dielectric, impedance and conductivity) of the material, collected at various temperatures (75–375 °C) in a wide frequency range (1 kHz–1MHz) have provided its conduction and relaxation behavior. The electric field dependent current density (J-E) characteristics suggest the Ohmic behavior while the field dependent polarization (P-E loop) confirms the ferroelectric nature of the studied material.

Electrical response of polymer functionalized ultrafine inorganic particles under frequency conditions: an in situ approach

Dielectric and field-dependent polarization response of palladium iodide nanoparticles under both in situ and ex situ condition.

Dielectric and magneto-dielectric properties of x [Co0.9Ni0.1Fe2O4] - (1-x) [Ba(Zr0.2Ti0.8)O3] particulate multiferroic composites

Present paper reports on synthesis and characterization of x(Co0.9Ni0.1Fe2O4)-(1-x)(Ba(Zr0.2Ti0.8)O3) multiferroic magneto-dielectric composite of ferrite and ferroelectric phase for x=0.1, 0.2 and 0.3 via hydroxide co-precipitation method. The well compacted disc shape samples of the MD composites are sintered with microwave sintering technique at 1100°C. These composites are investigated for their structural, micro-structural, dielectric, ferroelectric and magneto-dielectric properties. X-ray diffraction shows the presence of the peaks corresponding to both ferroelectric and ferrite phases in the composites. Temperature dependent dielectric spectra gives the two anomalies one at lower temperature (below 50°C) corresponds to the ferroelectric transition temperature and other at the higher temperature (above 350°C) corresponding to magnetic transition. The variation of dielectric constant and loss tangent with applied magnetic field between 0-1 tesla in the frequency range of 500 Hz to 1 MHz are investigated. Dielectric constant possesses contribution due to magnetic field dependent interfacial polarization and variations due to the induced stress which can be explained on the observed MD effect. Copyright © 2016 VBRI Press

Studies of structural, dielectric and impedance spectroscopy of Sr/ Zr modified BiFeO3 ceramics

Bismuth ferrite (BiFeO3) is the most commonly used multiferroics for multifunctional applications. The polycrystalline samples of co-doped (Sr/Zr) bismuth ferrite (BiFeO3) of a general chemical composition, Bi1-xSrx)(Fe1-xZrx)O3, x = 0.05, 0.1, 0.15, 0.20, were prepared using a standard solid-state reaction method. The basic structural data of the above synthesized electro-ceramics were obtained by X-ray diffraction data and pattern. The surface morphology of the samples was recorded at room temperature by a scanning electron microscope. The scanning electron microscope images show the uniform distribution of grains throughout the surface of the samples. Studies of dielectric and impedance properties of the samples at varying frequency (1 kHz–1000 kHz) and temperature (250C–300 °C) have provided many important information about the materials. The existence of ferroelectricity in the materials was studied by the electric field dependent polarization. The contributions of both grains and grain boundaries towards the total resistance and capacitive behavior of the compounds have been studied by analyzing the frequency and temperature dependence of impedance data.. Study of frequency-temperature dependence of ac-conductivity has provided the information on the type of conduction mechanism. The J–E characteristics of the samples provide the Ohmic behavior with slope closer to 1.

D 5 off-centering induced ferroelectric and magnetoelectric correlations in trirutile-Fe2TeO6

We present the rare existence of d5 off-centering induced weak ferroelectric polarization and demonstrate its correlation with observed magnetoelectric (ME) properties in the G type (TN ∼ 210 K) antiferromagnet Fe2TeO6 (FTO) compound. The origin of ferroelectricity (FE) is associated with both lattice and asymmetric electron density (ED) distribution around the ion cores. ME coupling is observed in magnetic field-dependent polarization, ME voltage, and magnetostrain measurements. Short-range magnetic ordering due to intrabilayer dimeric exchange coupling via the double oxygen bridged Fe–O1–Fe pathway is proposed to play a dominating role to exhibit the negative nonlinear magnetic field-dependent ME behavior at 300 K. Interbilayer exchange via Fe–O2–Fe pathways dominantly determines the hysteretic nonlinear magnetic field-dependent ME response below TN. The observed nonlinear ME coupling signifies magnetoelasticity as manifested in the temperature and magnetic field-dependent strain measurement. Hence, the rare existence of FE and magnetoelectric coupling by d5 ion is presented in FTO.

Shielding of external magnetic field by dynamic nuclear polarization in (In,Ga)As quantum dots

The dynamics of the coupled electron-nuclear spin system is studied in an ensemble of singly-charged (In,Ga)As/GaAs quantum dots (QDs) using periodic optical excitation at 1 GHz repetition rate. In combination with the electron-nuclei interaction, the highly repetitive excitation allows us to lock the electron spins into magnetic resonance in a transverse external magnetic field. Sweeping the field to higher values, the locking leads to an effective "diamagnetic" response of significant strength due to dynamic nuclear polarization, which shields the QD electrons at least partly from the external field and can even keep the internal magnetic field constant up to 1.3 T field variation. We model the effect through a magnetic field-dependent polarization rate of the nuclei, from which we suggest a strategy for adjusting the nuclear polarization through the detuning between optical excitation and electronic transition, in addition to tuning the magnetic field.

15 N SABRE Hyperpolarization of Metronidazole at Natural Isotope Abundance.

Signal Amplification By Reversible Exchange (SABRE) is gaining increased attention as a tool to enhance weak Nuclear Magnetic Resonance (NMR) signals. In SABRE, spin order is transferred from parahydrogen (H2 in its nuclear singlet spin state) to a substrate molecule in a transient Ir-based complex. In recent years, SABRE polarization of biologically active substrates has been demonstrated, notably of metronidazole - an antibiotic and antiprotozoal drug. In this work, we study 15 N SABRE polarization of metronidazole at natural isotope abundance. We are able to demonstrate significant 15 N polarization reaching 15 %, which corresponds to a signal enhancement of 46,000 at 9.4 T for the nitrogen atom with lone electron pair. Additionally, the other two N-atoms can be polarized, although less efficiently. We present a detailed study of the field dependence of polarization and explain the maxima in the field dependence using the concept of coherent polarization transfer at level anti-crossings in the SABRE complex. A study of spin relaxation phenomena presented here enables optimization of the magnetic field for efficient storage of non-thermal polarization.

All chemical solution deposition of epitaxial porous BiFe0.93Mn0.07O3 thin films

BiFeO3 as a type of single-phase room temperature multiferroic materials has aroused intensive investigations in recent years. Construction of porous BiFeO3 thin films is helpful for integration of other materials with desirable functionalities. Here, epitaxial BiFe0.93Mn0.07O3 (001) thin films were prepared on SrRuO3-buffered LaAlO3 (001) single crystal substrates by an all-solution chemical solution deposition, which is beneficial for large area thin film fabrication with low cost. Through addition of F-127 copolymer into the precursor solution, pores can be effectively introduced in BiFe0.93Mn0.07O3 (001) thin films while the epitaxy can be maintained. The amount of pores is gradually increased with increasing of the F-127 addition. The leakage current density is not obviously changed and the conduction mechanism can be well fitted through Ohmic behavior. Electric field dependent polarization hysteresis loops can be effectively maintained and the room temperature magnetic moment is obviously improved with the introduction of pores in epitaxial BiFe0.93Mn0.07O3 (001) thin films. The results will provide a facile route to fabricate large area epitaxial porous BiFeO3 thin films as an effective template for integration of other materials to realize desirable functionalities.

Combine effect of BaSnO3 and BaSeO3 substitution on structural and electrical properties of Bi0·5K0·5TiO3 ceramics

In this research article, structural (crystal structure, micro structure) and electrical (dielectric, impedance and conductivity) properties of BaSnO3 (BSn) and BaSeO3 (BSe) modified (Bi0·5K0.5) TiO3 ceramic (i.e., (1–2x)((Bi0·5K0.5)TiO3)+xBaSnO3+xBaSeO3 with x = 0, 0.05, 0.10, 0.15 (BKT-BSn-BSe) have been fabricated via a high-temperature cost effective mixed oxide reaction process. The structural, micro structural and electrical characteristics of the parent compound ((Bi0·5K0.5) TiO3) have significantly been influenced by the substitution of BSn–BSe (in equal ratio) in it over a high temperature (100–500 °C) and frequency (1 kHz–1 MHz) range. Structural analysis of the compounds, carried out by the room temperature X-ray diffraction (XRD) data, confirms the formation of single phase compounds with tetragonal structure. The surface morphology of the materials, exhibits the homogeneous distribution of grains (with few voids) throughout the surface of the materials. The presence of bulk and grain boundary effect of the material is confirmed by the nature of Nyquist plot. J-E characteristics of the compounds show a negative temperature co-efficient of resistance (NTCR) behavior in them, similar to that of a semi-conductor. The ferroelectric phenomena of the prepared materials are studied by field dependence of polarization (PE) hysteresis loop study.