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Sb-modified alkali bismuth titanate Li0.5Bi0.5−xSbxTiO3 (x = 0 and 0.1) compounds are prepared using the method of solid-state-reaction route. The XRD exploration in environmental conditions confirms the development of new compounds having single-phase orthorhombic crystal structures. Non-uniformly distributed grains are noticed in SEM micrographs for both compounds. The electric & dielectric behavior is analyzed by use of an impedance analyzer. The exploration of the dielectric behaviors of both compounds in a wide frequency range (100 Hz–1 MHz) & temperature range (30–500 °C) suggests that these characteristics are strongly dependent on frequency & temperature. Activation energy assessed from temperature variation of ac-conductivity in various zones recommends that the electric transport phenomenon obeys the Arrhenius equation and shows a mixed type of conductivity. [ABSTRACT FROM AUTHOR]

Sb-modified lithium bismuth titanate Li0.5Bi0.3Sb0.2TiO3 is prepared following the mixed oxide method. The development of a new compound with a single-phase orthorhombic crystal structure is approved from the XRD analysis at environmental temperature. The electrical behavior like dielectric and electrical conductivity are analyzed in a wide temperature as well as frequency range by the impedance analyzer, which exhibits that these properties effectively depend on frequency and temperature. The ac conductivity versus temperatures plots obeys the Arrhenius relation and confirm the presence of the mixed type of conductivity process like space charge conductivity created from oxygen ion vacancies, ionic-polaronic conductivity, and so on, in the sample. Ac conductivity versus frequency spectra is as per Jonscher's Universal Power law. [ABSTRACT FROM AUTHOR]

The polycrystalline sample Bi4Ti2.8Sn0.2O12 was synthesized using the solid-state reaction method at 850 °C. The sample was formed in a single-phase orthorhombic structure and having space group B2ab, according to the XRD study at room temperature. The dielectric behaviors of the sample have been studied for the frequency range 1 kHz-1 MHz and a wide range of temperature 25-500 °C, which provide some important properties of the synthesized sample. The Nyquist plots provide the effect of grains and grain boundaries to the total resistance and capacitance of the synthesized compound. From ac-conductivity studies, various kinds of conduction mechanisms have been examined. The J–E characteristics support the Ohmic character of the prepared sample. The ferroelectric property at room temperature at frequency 50 Hz has been studied from polarization study. [ABSTRACT FROM AUTHOR]

In this article, a comprehensive investigation of structural as well as electrical properties of Sm2O3-modified Bi4Ti3O12 (i.e. Bi3.8Sm0.2Ti3O12), a member of the Aurivillius family has been synthesized by using a mixed-oxide reaction technique. The sample crystallizes in orthorhombic symmetry (space group, B2ab). The electrical behaviors of the pure material, bismuth titanate are improved considerably by substituting a small amount (20%) of trivalent rare-earth (i.e. samarium) ion at its Bi-site. The electrical characteristics of the compound at different temperatures (25–500 °C) over a wide-ranging frequency (1 kHz–1 MHz) have shown several interesting features. The compound displays higher dielectric constant as well as lower tangent loss. The presence of ferroelectricity in the material is established by the P–E hysteresis loop. The J–E characteristics at various temperatures display the Ohmic conduction with a low leakage current that makes the material useful in several electronic industries. [ABSTRACT FROM AUTHOR]

In this article, the synthesis (through a mixed oxide route, calcination temperature = 850 °C, sintering temperature = 870 °C, for time= 6 h) and characterization (structure, dielectric, and electrical properties) of Gd modified bismuth titanate Bi4Ti3O12 of a chemical composition Bi3.8Gd0.2Ti3O12 of Aurivillius family in ceramic form have been reported. The development of an orthorhombic structure (with a minor secondary phase) with a space group B2ab has been confirmed by analyzing room temperature X-rays diffraction pattern/data. Studies of some electrical parameters like loss tangent, dielectric constant, electric impedance, and conductivity have provided valuable data and information on conduction mechanism, structure-properties relationship, etc., in the 25–500° C temperature range at different frequencies (1 kHz − 1MHz). The presence of grain, grain boundary is confirmed from the Nyquist plot. The Nyquist plot also confirms the existence of non-Debye relaxation in the material. The frequency and temperature significantly impact the material's various properties (dielectric and electrical). [ABSTRACT FROM AUTHOR]

The solid-state reaction route created the lead-free dielectric material CaBiLaNbVO9 at a high temperature. The polycrystalline compound belongs to a monoclinic crystal structure having dimensions a = 10.6738 Å, b = 10.4488 Å, c = 7.1793 Å, and V = 798.04 Å3. The grain size is calculated to be 1.1029 µm. The doping of La3+ at the Bi-site and divalent cation Ca2+ substituted at site-A and Nb5+, V5+ in the site-B of ABO3 has considerably modified the structural, dielectric, and electrical conduction mechanism. The study of ac conductivity (frequency-temperature characteristics) shows CBH (correlated barrier hopping) and NSPT (non-overlapping small polaron tunneling) conduction mechanisms. Non-Debye type relaxation has been observed using impedance analysis. The modulus and impedance study have been used to confirm the short-range order of charge carriers. The average transmittance of the compound is about 82–84%, and absorption is in the range of 0.1–1.0% in the visible area applicable for transparent conductive oxide. The energy band gap is 2.73 eV. The analysis of the resistive and capacitive properties indicates the material is an electronic component for the creation of devices. [ABSTRACT FROM AUTHOR]

The polycrystalline sample Bi4Ti2.8Sn0.2O12 was synthesized using the solid-state reaction method at 850 °C. The sample was formed in a single-phase orthorhombic structure and having space group B2ab, according to the XRD study at room temperature. The dielectric behaviors of the sample have been studied for the frequency range 1 kHz-1 MHz and a wide range of temperature 25-500 °C, which provide some important properties of the synthesized sample. The Nyquist plots provide the effect of grains and grain boundaries to the total resistance and capacitance of the synthesized compound. From ac-conductivity studies, various kinds of conduction mechanisms have been examined. The J–E characteristics support the Ohmic character of the prepared sample. The ferroelectric property at room temperature at frequency 50 Hz has been studied from polarization study. [ABSTRACT FROM AUTHOR]

Lanthanum substituted Bismuth Nickel Titanate (BNTO) ceramic, that is, (Bi 0.8La0.2)(Ni0.5Ti0.5)O3 (abbreviated as BLNTO 20) was successfully synthesised by solid-state reaction technique. The phase formation of the ceramic compound was confirmed by the X-ray diffraction study. The FESEM micrograph depicts the homogeneous spreading of the dissimilar size grains on the surface of the compound. The dielectric characteristics of ceramic were observed by computing the dielectric outcome in selected range of frequency and temperature. The frequency/temperature dependent conductivity plots of the ceramic compound satisfy the universal Jonscher's power law. P-E Loop tracer was used to study the ferroelectric nature, which suggests the possibility of enhanced ferroelectric behaviour of the compound. Therefore, based on the enhanced ferroelectric features due to La doping ceramic compound may have promising performance for further electronic device application. [ABSTRACT FROM AUTHOR]

With the increasing trends of integrated circuit densification, device miniaturization, and exponential growth of microelectronic components there is a huge responsibility on the part of material researchers to derive, design, and develop new materials. Materials that can overcome the existing limitations in the present compounds available in the market or can expedite the process of material fabrication are of great interest. This feat can be achieved by the fabrication of new materials, and analysis of various characterizations viz. (structural, dielectric, transport behavior, and impedance spectroscopy). With this perspective, in this communication, a high permittivity dielectric material belonging to the Y-Ba-Cu-O ternary systems where barium is replaced by calcium (Y2CaCuO5) is synthesized using solid-state reaction route. X-ray diffraction, scanning electron micrograph, and energy-dispersive X-ray spectroscopic study confirm the phase and microstructure of the sample. The observed higher value of the dielectric constant is understood from Koop's phenomenological theory and internal barrier layer capacitance model. The dispersive behavior of conductivity is interpreted by Jonscher's power law. Overlapping large polaron tunneling model for conduction is observed. Impedance spectroscopy analysis reveals non-Debye type of relaxation with variable time constants. According to Nyquist plots; up to 250 °C only grain effect (bulk) is dominantly present; however, at higher temperatures, the contribution from both grain and grain boundary is seen. [ABSTRACT FROM AUTHOR]

A lead-free brownmillerite ferroelectric material LiBiFe2O5 (LBFO) has been synthesized via a solid-state reaction technique. Using the procedure of N-TREOR method of X-ray diffraction, the crystal structure of the prepared sample is found to be monoclinic with lattice parameters: a = 13.6726 Å, b = 4.1560 Å, c = 8.5317 Å, and β = 102.89˚. Based on analysis of electrical data, the existence of Koop's and Maxwell–Wagner relaxation phenomena and dielectric relaxation in the material has been confirmed. This analysis has also shown a high impact of the dielectric permittivity (ϵr) and low tangent loss (tanδ) on using the material in some electronic devices. A detailed study of the frequency-temperature-dependent ac conductivity has suggested the presence of Jonscher's universal power law in the material. As the material has thermistor constant (β) values of 4019.26, 11535.75, and 484.36 in different temperature ranges indicating high-temperature NTC thermistor application. [ABSTRACT FROM AUTHOR]

Double pervoskite BiHoZnCeO6 (BHZCO) has been synthesized by the cost-effective solid state reaction method. It is characterized by a combination of techniques including powder X-ray diffraction (PXRD), dielectric, thermal analysis, and scanning electron microscopy (SEM). The fundamental structural symmetry and the cell parameter refinement for the BHZCO is investigated by analyzing the PXRD data with the help of widely used "MAUD" software. As per the PXRD-analysis, the Fig. 1a and b of the published paper Applied Physics A (2020) 126:655, clearly shows that it crystallizes with an orthorhombic crystal lattice with space group of Pca21, whose profile resembles with another bismuth-based double pervoskite Bi2WO6; crystallography open database (COD) ID: 2,108,252. However, in the CP paper, the author claims that BHZCO should have the cubic Fm-3m crystal structure, surprisingly claims that the phase is CeO2:Bi,Ho,Zn with unknown amount of dopants. Hence, in the present communication attempts have been made to compare both the cell structures for the BHZCO. [ABSTRACT FROM AUTHOR]

In this communication, the synthesis of the Ca3CuTi4O12 (CCTO) ceramic by a conventional solid-state reaction method is reported. The XRD analysis confirms an orthorhombic structure with average crystallite size and lattice strain are about 96.5 nm and 0.116% respectively. Field emission scanning electron microscope (FESEM) analysis confirms both weight and atomic percentage of all constituent elements and agglomeration rate of grains (DSEM /DSC = 7.4); which may be a possible reason for the observed elevated dielectric constant. No trace of phase transition is observed from the Raman lines; so, the observed giant dielectric constant may not be related to the displacement of Ti ions. The energy bandgap is about 3.72 eV, which may suitable for photovoltaic applications. The semiconducting nature is confirmed from the both Nyquist and Cole–Cole plots. Thermistor constant (β), sensitivity factor (α), and stability factor of the sample were calculated; which confirms the characteristics of the NTC thermistor. [ABSTRACT FROM AUTHOR]

The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO3 ceramics. The studied sample was prepared by a citrate gel method. Structural and microstructural properties are analyzed from the XRD pattern and SEM micrograph. The anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe 3 + ions driven by the oxygen vacancy mediated Fe 3 + –V o –Fe 3 + exchange interaction A giant dielectric permittivity in the order of ∼ 105 was observed in the sample even at the room temperature for 100 Hz. The colossal dielectric constant in LaFeO3 is mainly driven by the internal barrier layer capacitor (IBLC) formation. The formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain, which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance analysis. The non-Debye-type relaxation process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation peak. The relaxation time for both the grain and grain boundary effect was also calculated. In addition to this, we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation process dominated by the short-range movement of charge carriers. [ABSTRACT FROM AUTHOR]

A solid-state reaction technique was used to make cerium (Ce) modified strontium manganite SrMn0.9Ce0.1O3 (SMCO). The Goldschmidt's tolerance factor of 0.95 and the Sure Independence Screening and Sparsifying Operator (SISCO) tolerance factor of 4.02, both are within the permissible range. SMCO's average crystallite size and micro-lattice strain were determined to be 59.6 nm and 0.439%, respectively. Analysis of the micrograph captured by the scanning electron microscopy (SEM) technique revealed the average grain size of 19.2 μm of the SMCO. The optical bandgap of the SMCO was found to be 4.53 eV for direct allowed transition for photovoltaic applications. The existence of + 4 oxidation state of both Ce and Mn in the SMCO has been ascertained by the X-ray photoelectron spectroscopic technique. The bulk resistance (Rb) decreases from 1.02 × 105 to 1.09 × 103 Ω on increasing the temperature supports the negative temperature coefficient of resistance (NTCR). The semiconductor nature of the material is further validated by the semicircular pattern of Nyquist and/or Cole–Cole plots. The observed change in activation energy with temperature proposes that the conductivity (σac) behavior of the material is due to the thermal activation phenomenon. The evaluation of the field-dependent polarization (P–E) hysteresis loop was also carried out to obtain the coercivity, remnant polarization, maximum electric field, and maximum (saturation) polarization which support the possibility of ferroelectricity in the material. The leakage–current plots between (log J versus log E) at selected temperatures support the existence of Ohmic conduction in the material at low voltages. [ABSTRACT FROM AUTHOR]

In the present work, we have mainly carried out comprehensive studies of structural, microstructure, dielectric, electrical (impedance, modulus, conductivity, leakage current) characteristics of the Fe-modified Y2BaCuO5 of a chemical composition of YBaCuFeO5, fabricated by a. cost-effective ceramic fabrication technique. Room-temperature X-ray diffraction studies reveal that it crystallizes in tetragonal crystal system. SEM and EDAX of the sample provide the micro structural details of the ceramic sample with homogeneous grain and grain-boundary distribution. Dielectric and impedance characteristics have been studied over a frequency range of (1 kHz–1 MHz). Maxwell–Wagner polarization effect observed from the frequency response of polarization study is also evident from the grain and grain-boundary resistances obtained from Nyquist plot. Electric modulus studies and scaling behavior with details of the relaxation time of the sample has been discussed. Leakage current behavior has also been discussed and the type of mechanism responsible for conduction is indicated to be space-charge limited conduction mechanism. Owing to the increasing demand for miniaturization of electronic components and the versatility of applications; design and fabrication of new dielectric ceramics is of great interest to us. Major applications include sensors, actuators, transducers and capacitors. These applications require the dielectric ceramics to have high value of dielectric constant, low dielectric loss, high Tc value (in case of ferroelectric sample) etc. So far detailed analysis of electrical transport behavior, impedance characteristics, I–V (current–voltage) characteristics and leakage current behavior within a temperature range from 25 °C -400 °C for YBaCuFeO5 has not been carried out. High-K dielectric materials finds major applications in central processing units, dynamic random access memories, multilayered ceramic capacitors that are the building blocks of printed circuit boards. In such a scenario exploring the dielectric, impedance and electrical behavior of the synthesized ceramic sample YBaCuFeO5 at room and higher temperature can provide significant insights which can help broaden the amount of work carried out for this material. In our synthesized sample we have observed a dielectric constant of 395 at 50 kHz at room temperature and high value of 8514 is observed at a higher peak around 231 °C for the same frequency. [ABSTRACT FROM AUTHOR]

The Rietveld refined X-ray diffraction pattern of (Bi0.5Ba0.25Sr0.25)(Ti0.25Mn0.25Fe0.5)O3 sample synthesized through the high temperature mixed oxide solid state route confirms the tetragonal (space group: P4mm) symmetry. The scanning electron micrographs clearly explain the morphology of the sample. Temperature and frequency dependent dielectric parameters as well as the PE-hysteresis loop explain the validity of Curie Weiss law and ferroelectricity present in the material below the TC. The non-Debye type of relaxation, effect of grain and grain boundary on impedance is illuminated by the impedance analysis. The Field-leakage current (JE) characteristics revealed the space charge limited and Ohmic-type conduction process occurring in the material. [ABSTRACT FROM AUTHOR]

The polycrystalline sample (Ba0.05Bi0.95)(Fe0.95Zr0.05)O3 was prepared by solid state reaction method at 850 °C. The crystal structure and surface morphology of the sample were obtained by using X-ray diffractometer and a scanning electron microscope respectively. The frequency dependence of electrical parameters using impedance spectroscopy provides the dielectric behavior and grain and grain boundary effect toward resistance and capacitance of the sample. The conduction mechanism of the sample was studied from frequency dependent ac conductivity. The ferroelectricity of the sample was studied by p-E loop at room temperature. The slope from J–E characteristics was found to be nearly equal to 1. [ABSTRACT FROM AUTHOR]

The Rietveld refined X-ray diffraction pattern of (Bi0.5Ba0.25Sr0.25)(Ti0.25Mn0.25Fe0.5)O3 sample synthesized through the high temperature mixed oxide solid state route confirms the tetragonal (space group: P4mm) symmetry. The scanning electron micrographs clearly explain the morphology of the sample. Temperature and frequency dependent dielectric parameters as well as the PE-hysteresis loop explain the validity of Curie Weiss law and ferroelectricity present in the material below the TC. The non-Debye type of relaxation, effect of grain and grain boundary on impedance is illuminated by the impedance analysis. The Field-leakage current (JE) characteristics revealed the space charge limited and Ohmic-type conduction process occurring in the material. [ABSTRACT FROM AUTHOR]

The polycrystalline sample (Ba0.05Bi0.95)(Fe0.95Zr0.05)O3 was prepared by solid state reaction method at 850 °C. The crystal structure and surface morphology of the sample were obtained by using X-ray diffractometer and a scanning electron microscope respectively. The frequency dependence of electrical parameters using impedance spectroscopy provides the dielectric behavior and grain and grain boundary effect toward resistance and capacitance of the sample. The conduction mechanism of the sample was studied from frequency dependent ac conductivity. The ferroelectricity of the sample was studied by p-E loop at room temperature. The slope from J–E characteristics was found to be nearly equal to 1. [ABSTRACT FROM AUTHOR]

In the present report, an attempt has been made to develop (via synthesis and characterization) a lead-free multifunctional material by introducing Ni in BaTiO3 of a composition of (Ba0.5Ni0.5)TiO3 for the temperature sensor and bandwidth applications. The phase analysis using X-ray diffraction data reveals the mono-phase nature of the developed system in the tetragonal crystal symmetry. The variation of structural parameters such as lattice constant, unit volume, change in tetragonality ratio from 1.0082 to c/a = 1.5792, are evidence of structural distortion generated in the unit cell of BaTiO3 on the addition of nickel at its Ba-site of the parent compound. This distortion significantly affects the dielectric, ferroelectric, impedance, and conductivity characteristics of barium titanate. The electron microscopic studies of the material show the compactness and uniform distribution of grains almost the same size over the surface of the pellet sample. The frequency-temperature-dependent studies of the material exhibit that ferroelectric-paraelectric phase transition temperature (Tc) of BaTiO3 (~ 120 °C) has been diffused or shifted, and hence no phase transition or dielectric anomaly is observed in the experimental temperature range (30–500 °C) in Ni-rich barium titanate (i.e., Ba0.5Ni0.5)TiO3. The relative permittivity even at 450 °C is found to be in the order of 103 with conductivity in the order of 10–4 Ω cm−1. However, room temperature hysteresis loop provides the saturation polarization of (Ps = 3.1416 μC/cm2), remnant polarization (Pr = 0.8478 μC/cm2) and coercive field (EC = 87.76 kV/cm). The analysis of various electrical data (parameters), such as relative permittivity, loss tangent, impedance as a function of temperature and frequency has provided dielectric relaxation and conduction mechanism in the material. Based on the above parameters, it may be concluded that the material can be a suitable candidate for multifunctional applications like temperature sensors, bandwidth, etc. [ABSTRACT FROM AUTHOR]

BaBiSb3Ti4O15 is a Bi-based Sb substituted Barium Bismuth Titanate ceramic is processed by mixed oxide process, calcined at 850 °C and subsequently sintered at 875 °C temperature. Room temperature XRD study confirms the formation of single-phase compound. The SEM micrograph shows uniformly distributed grains over the surface of the compound. Dielectric characteristic is studied in a wide frequency (100 Hz–10MHz) and temperature (30 °C–500 °C) range. Phase transition broadening is observed on substitution of antimony ion at bismuth site indicating diffuse phase transition in the material. From the appearance of P ∼ E loop, the existence of ferroelectricity in the material is confirmed. The complex impedance plots inform the impact of the grain and grain interface in the resistive and capacitive behavior of the compound. Negative temperature coefficient of resistance (NTCR) characteristics are noticed from the impedance study confirming the semiconductor-like behavior of the compound. [ABSTRACT FROM AUTHOR]

Studies of dielectric, optical and ferroelectric characteristics of trivalent Bi/Sm-modified barium titanate complex perovskite of a composition Bi0.5Ba0.5Sm0.5Ti0.5O3 (BBSTO), synthesized by adopting a mixed oxide (solid state) reaction technique, have been reported here. A single-phase tetragonal (space group P4mm) symmetry of BBSTO, after the evaluation of X-ray diffraction (XRD) data and pattern by Rietveld refinement, has been proposed. The microstructural analysis of pellet sample of BBSTO, carried out by field emission scanning electron microscope (FE-SEM), has shown uniform distribution and compactness of grains of varying size. Analysis of Fourier transform infrared spectrum of the material has provided the stretching vibration of Ba–Ti–O and O–Ti–O bonds, BiO6 (octahedral) as well as the bending vibration of Ti–O in octahedral [TiO6]2− of BaTiO3. The UV–visible absorption spectra of the material have been used to evaluate the optical band gap of 1.78 and 1.56 eV for the direct and indirect allowed transition, respectively. The analysis of dielectric and electrical data, obtained in a wide range of temperature (25–500 °C) at different frequency (1 kHz–1000 kHz), exhibits various characteristics including dielectric relaxation and a ferroelectric phase transition. The mixed temperature coefficient of resistance (TCR) behavior, both negative-TCR and positive-TCR is observed in the BBSTO perovskite. The conduction mechanism of the material was studied with the help of the Jonscher's power law. The conduction mechanism was also found to follow the correlated barrier hopping (CBH) model. The logJ versus logE plots were analyzed to understand the leakage current behavior of the material with the help the SCLC (space charge-limited conduction) mechanism and Schottky mechanism. [ABSTRACT FROM AUTHOR]

The synthesis of novel perovskite Bi0.5Ba0.5Gd0.5Ti0.5O3 (BBGTO) was carried by the cost-effective solid-state reaction method. The Rietveld refinement of the X-ray diffraction peaks suggests that BBGTO crystallizes with a tetragonal crystal structure. The crystallite size of 78.60 nm for the BBGTO perovskite is being computed by the application of Scherrer relation. The presence of stretching, bending vibrations of Ti–O in octahedron [TiO6]2− and stretching vibrations of BiO6 (octahedral) is realized by the analysis of the FTIR absorption bands. Tauc's plot using the UV–Visible DRS data of BBGTO suggests the optical bandgap of 2.29 eV and 1.87 eV for direct and indirect allowed transition, respectively. The dielectric permittivity plot with temperature showed a good broad characteristic peak justifies a possible diffuse type of ferroelectric–paraelectric phase transition in BBGTO. The ferroelectric behavior of BBGTO perovskite is further validated by a polarization–electric field loop (PE loop). The present perovskite exhibited both negative and positive temperature coefficient of resistance. The investigation of Jonscher's power law suggests that the BBGTO perovskite follows the overlapping large polaron tunneling OLPT model conduction mechanism. The electrical parameters like capacitance and resistance of grain boundary and grain of BBGTO were obtained by simulating the experimental impedance data with an equivalent circuit of {(CQR) (CR)}. The bulk resistance (Rb) steadily decreases from 4.978 kΩ at 25 °C to 1.262 kΩ at 500 °C. The current density versus applied electric field (J–E) plot was also investigated to understand the SCLC (space charge limited conduction) mechanism of Bi0.5Ba0.5Gd0.5Ti0.5O3. [ABSTRACT FROM AUTHOR]

Nowadays, several research groups are extensively trying to develop by synthesizing and characterizing single/co-doped single-phase bismuth ferrite (BFO) in order to get a highly efficient eco-friendly multifunctional devices. In this process, this report is an attempt to provide the detailed studies of structural, dielectric, impedance and ferroelectric properties of Bi(Fe0.85Dy0.15)O3 ceramic fabricated via the solid-state reaction method. Analysis of X-ray diffraction (XRD) data confirms a single phase of orthorhombic symmetry. The average crystallite (particle) size is found to be in the order of ~ 41 nm. The field emission scanning electron microscopy (FE-SEM) spectrum shows a homogeneous grain distribution of the sample. The elemental composition examined by means of energy dispersive X-ray spectroscopy (EDXS) shows the existence of constituent elements of the sample. The electrical measurements and analysis, carried out using a computer-controlled phase sensitive multimeter (PSM) in a frequency range of 1 kHz–1 MHz at different sets of temperature (25–325 °C), provide many interesting features to explain further conduction mechanism. The dielectric analysis exhibits high value of dielectric constant (ɛr) and small value of dielectric loss (tanδ). Due to the effect of electronic and space charge polarization, the ɛr value falls with an increasing frequency. The frequency–temperature dependence of impedance and electrical modulus analysis reveals the presence of semiconductor nature and non-Debye type of relaxation process in the sample. The analysis of ac-conductivity (σac) with respect to frequency and temperature obeys the universal Jonscher's power law. The electric polarization study shows an enhancement in ferroelectric property of the material. Hence, based on the significant enhancement in electrical and ferroelectric properties of the Bi(Fe0.85Dy0.15)O3 material, the material may be considered for some applications. [ABSTRACT FROM AUTHOR]

The synthesis of novel perovskite Bi0.5Ba0.5Gd0.5Ti0.5O3 (BBGTO) was carried by the cost-effective solid-state reaction method. The Rietveld refinement of the X-ray diffraction peaks suggests that BBGTO crystallizes with a tetragonal crystal structure. The crystallite size of 78.60 nm for the BBGTO perovskite is being computed by the application of Scherrer relation. The presence of stretching, bending vibrations of Ti–O in octahedron [TiO6]2− and stretching vibrations of BiO6 (octahedral) is realized by the analysis of the FTIR absorption bands. Tauc's plot using the UV–Visible DRS data of BBGTO suggests the optical bandgap of 2.29 eV and 1.87 eV for direct and indirect allowed transition, respectively. The dielectric permittivity plot with temperature showed a good broad characteristic peak justifies a possible diffuse type of ferroelectric–paraelectric phase transition in BBGTO. The ferroelectric behavior of BBGTO perovskite is further validated by a polarization–electric field loop (PE loop). The present perovskite exhibited both negative and positive temperature coefficient of resistance. The investigation of Jonscher's power law suggests that the BBGTO perovskite follows the overlapping large polaron tunneling OLPT model conduction mechanism. The electrical parameters like capacitance and resistance of grain boundary and grain of BBGTO were obtained by simulating the experimental impedance data with an equivalent circuit of {(CQR) (CR)}. The bulk resistance (Rb) steadily decreases from 4.978 kΩ at 25 °C to 1.262 kΩ at 500 °C. The current density versus applied electric field (J–E) plot was also investigated to understand the SCLC (space charge limited conduction) mechanism of Bi0.5Ba0.5Gd0.5Ti0.5O3. [ABSTRACT FROM AUTHOR]

The selenium (Se)-modified 0.5BiFeO3–0.5(BaSr)TiO3 was synthesized employing a high-temperature solid-state technique. Structural analysis (through Rietveld refinement) of the room-temperature X-ray diffraction pattern and data of the material confirms the tetragonal (P4mm) symmetry of the compound. Studies of scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDS) data reveal the nature and characteristics (i.e., size, shape and distribution of grains, grain boundaries, voids and presence of elements, etc.,) of surface morphology and structure of the compound. Detailed analysis of temperature and frequency dependence of dielectric and impedance data exhibits the relaxor type of ferroelectric behavior and semiconductor (negative temperature coefficient of resistance) nature of the material. The material is found to have high resistivity and low dielectric (tangent) loss. Study of the temperature dependence of leakage current characteristics (i.e., electric field dependent current density) shows the leaky behavior of the material. The Se-modified 0.5BiFeO3–0.5(BaSr)TiO3 (BFBST), compared to its components (BFBST and pure BiFeO3), material possesses different types of conduction process, like space charge limited (SCLC), Ohmic, Hopping type. Poole–Frenkel emission (PFE) and Schottky emission (SE) fitted data give an evidence/idea about the bulk-limited and interface-limited conduction mechanism present in the system. The energy gap values (Eg) of Se substituted BFBST and BiFeO3 are found to be 0.55 eV and 0.78 eV, respectively, in the low-temperature range. [ABSTRACT FROM AUTHOR]

A non-lead electronic sample with chemical composition Bi(Ni2/3V1/3)O3 (BNV) has been fabricated via a conventional ceramic technology. The resistive, capacitive and conducting properties of the specimen are examined experimentally. The formation of the sample with orthorhombic crystal system is ensured through X-Ray diffraction spectrum. Detailed analysis of the temperature-frequency dependent dielectric properties affirms the fabricated specimen as a dielectric. The conductivity study gives information about the nature and conduction mechanism of the fabricated dielectric. The impedance spectroscopic technique reveals the role of grain and grain boundaries on the capacitive and resistive properties of the sample. The current density based electric field characteristics show that the sample has low leakage current density (1.2 × 10−9 A/cm2). This dielectric component entails high dielectric permittivity (98 × 102), lower loss (8) and excellent excitation response to an electric field, thus it props up to be a potential component in different high-temperature industrial applications. [ABSTRACT FROM AUTHOR]

This communication mainly reports the synthesis and characterization of dysprosium (Dy)-doped bismuth ferrite [i.e., Bi(Fe0.95Dy0.05)O3 (referred as BFDO5)] compound. A conventional high-temperature solid-state reaction technique has been utilized for synthesizing the material at a temperature of 800 °C. The structural study of the prepared sample, carried out using X-ray diffraction data, reveals the creation of a single-phase compound having an orthorhombic crystal structure. The average crystallite size, obtained from the measurement of high-intensity X-ray diffraction peaks of the BFDO5 material, was found to be 38 nm. The purity of the prepared compound and concentration of its constituent elements were confirmed by energy dispersive X-ray spectroscopy (EDXS) data. The field effect scanning electron microscope (FESEM) image clearly shows the surface morphology and regular distribution of the composite grains over its surface. Detailed analysis of the dielectric and impedance data, measured in a broad range of frequency (1–1000 kHz) and temperature (25–500 °C), has shown a significant improvement in the dielectric and electrical properties of the prepared material. The electrical polarization measurement, done by P–E hysteresis loop tracer, shows the existence and enhancement of ferroelectric property of the material. Room temperature measurement of its magnetization was carried out by using vibrating sample magnetometer that shows a significant enhancement in a remnant magnetization as compared to pure bismuth ferrite. [ABSTRACT FROM AUTHOR]

A multiple cation containing sample as [(Pb0.8Dy0.1Bi0.1)(Fe0.2Ti0.8)O3] is fabricated by adopting the solid-state reaction process. The crystallographic structure, crystallite size, morphology, dielectric behavior, conductivity, polarization, impedance as well as electric modulus spectroscopy are experimentally observed for this fabricated composition. The crystal structure of the specimen is observed to be tetragonal from X-ray diffraction. The micrograph shows the presence of polycrystalline microstructure with uniform distributed grains. The impedance spectroscopy analysis as a function of temperature (100–450 °C) and frequency (1–1000 kHz) helps to signify the resistive and capacitive behavior of the compound. The nature of the prepared specimen and conduction mechanism is illustrated through AC conductivity study. The modulus analysis elucidates the existence of non-Debye dielectric relaxation nature in the synthesized compound. The compound possesses appreciable value of loss tangent and remnant polarization, i.e., 0.02 and 0.014 µC/cm2, with high value of dielectric constant at room temperature. The dysprosium doping entails stability with interesting electrical and dielectric properties. The preliminary capacitive characteristic has been elucidated, thus making it a stronger contender for functional device applications. [ABSTRACT FROM AUTHOR]

A standard solid-state ceramic technology (i.e., high-temperature solid-state reaction method) was used to fabricate new bismuth layer Aurivillius compound, BiLa2TiVO9. The formation of a single phase with an orthorhombic structure was confirmed by the X-ray diffraction structural analysis. The tangent loss measured at 200 °C is found to be in between 0.03 and 0.05 in the frequency ranging from 1 kHz to 1 MHz. The dielectric constant is found to be around 300 at room temperature. The resistance and reactance parts of complex impedance have been determined by the complex impedance spectroscopy (CIS) techniques. The electric modulus spectroscopy study of the compound confirmed the presence of the short range displacement of charge carriers. Jonscher's power law fitting has been used to verify our experimental data of conductivity spectra. The nature of variation of exponent (n) obtained from the fitting follows the correlated barrier hopping as the predominant conduction mechanism in the sample. Room-temperature polarization loop confirms the ferroelectric nature of the sample. [ABSTRACT FROM AUTHOR]

The polycrystalline (with nanosized particles) samples of Pb(Sc0.5Nb(1-x)/2Tax/2)O3 (PSNT) (x=0, 0.3, 0.5, 0.7, and 1) were prepared using mechanical activation system and the mixed oxide routes. The compounds were found in rhombohedral structure with the presence of a small amount of pyrochlore phase. The changes in the microstructures were observed on increasing Ta contents in PSNT. Studies of dielectric properties as a function of temperature (200–600 K) and frequency (1 kHz–1 MHz) of the sintered samples of different compositions have enabled us to determine the phase transition behavior of relaxor type with the diffuse phase transition for x<=0.3. For higher values of x (>=0.5) the diffuse phase transition suggested nonrelaxor type of phase transition in PSNT. The changes in the dielectric/relaxor properties of the compounds are compositional and sintering temperature dependent. The room temperature Raman measurement confirmed the presence of nanosized regions, diffuse phase transition, and relaxor ferroelectric characteristic of PSNT. [ABSTRACT FROM AUTHOR]

(Pb0.97Sr0.03)(Zr0.05Ti0.95)O3 nanocrystalline powder was prepared by a solution based chemical method. Preliminary x-ray diffractogram analysis of some aspects of crystal structure showed that a single-phase compound was formed exhibiting a tetragonal system. Impedance spectroscopy study showed the presence of both bulk and grain boundary effects in the material, which is also evident from the scanning electron microscope micrographs. The bulk conductivity indicates an Arrhenius-type thermally activated process. The ac conductivity spectrum obeyed the Jonscher power law. Modulus analysis indicated the possibility of hopping mechanism for electrical processes in the system with a nonexponential type of conductivity relaxation. [ABSTRACT FROM AUTHOR]

PbBi2Ta2O9 ceramic samples were fabricated by high-temperature mixed oxide method. X-ray diffraction determines the structure as orthorhombic. The scanning electron microscopy confirms the formation of densely packed grains in the sample. The dielectric measurements, complex impedance and complex modulus study were carried out in a frequency range of 1 kHz–1 MHz and a temperature rangeof 25–500°C. The conduction mechanism of the material is discussed in details using variable range hoping, nearest neighbor hopping relaxation model and dc activation energy at two different temperature regimes. From the J-E characteristics studies, the occurrence of non-linear curves endorses the non-Ohmic nature of the material. [ABSTRACT FROM AUTHOR]

We have investigated the electric field and temperature dependence of dielectric, impedance and conduction characteristics of a lead-free complex distorted perovskite (Bi1/2K1/2)(Zn1/2W1/2)O3 ceramic. The material was synthesized by using a standard high-temperature ceramic technology. Analysis of x-ray diffraction data and patterns collected at room temperature has provided the information on the formation of a distorted perovskite with an orthorhombic crystal system. Dielectric and impedance spectroscopy techniques have been utilized to study the effect of frequency and temperature on the dielectric, impedance and transport (conduction) characteristics of the compound. The mechanism of dielectric relaxation phenomenon in the compound has been analyzed using the dielectric and impedance data collected in a wide range of temperature (100-500°C) and frequency (1 kHz-1 MHz). Analysis of temperature-frequency-dependent Nyquist (impedance) plots has shown an important role of grains (bulk) and grain boundaries in the capacitive and resistive characteristics of the material. Based on the frequency-dependent electrical modulus and impedance data of the compound, the dielectric relaxation of non-Debye type has been suggested. The nature of the temperature- and frequency-dependence of ac conductivity of the compound follows Joncher’s power law. The fabricated compound has some important dielectric characteristics which can potentially be used for electronic devices. [ABSTRACT FROM AUTHOR]

In the present communication, studies of some physical properties (i.e., crystal data, permittivity, impedance, electrical cobnduction and magnetic) of a multiferroic material with a chemical composition (SmLi)1/2(Fe2/3Mo1/3)O3 have been reported. Thermogravimetric analysis of the compound, prepared by cost effective ceramic technology processing, was executed to check the mass loss as well as the required decomposition temperature of the ingredients. An analysis of X-ray spectra or pattern suggests that the crystallization phase or cystal system of the compound at room temperature is orthorhombic. The broad studies of dielectric properties {relative dielectric constant (εr), and tangent loss (tan δ)} display their independence of temperature and frequency in the rage of (30-375 °C) and (1 kHz-1 MHz) respectively. The impedance spectroscopic technique has provided a considerable significant information regarding the grain, grain boundary contribution within the sample and relaxation mechanism of the compound. The occurrence of negative temperature coefficient behaviour (NTCR) is depicted by the further analysis of impedance parameters. The frequency-temperature dependence of conductivity follows the Johnson’s power Universal law. The Arrhenius plot (i.e., variation of electrical conductivity with temperature) is used to calculate the activation energy. Analysis of magnetization (M-H) loop shows weak ferromagnetism of the compound. The material possesses significantly high magnitude of magnetoelectric coefficient of 3.0 mV Cm− 1 Oe− 1. [ABSTRACT FROM AUTHOR]

Using standard ceramic technologies, above materials (i.e., Ni/Ti or Co/Ti-modified BiFeO SB 3 sb ) have been synthesized and characterized (physical properties including basic crystal structure). Further, it should be noted that the proposed compound of Bi SB 25 sb FeO SB 39 sb of Ni/Ti or Co/Ti in [[1]] needs different amounts of ingredients, other than those taken for reported ones, to maintain the stoichiometry ratio. J Mater Sci: Mater Electron (2022). https://doi.org/10.1007/s10854-022-08329-z 2 Shukla A, Kumar N, Behera C, Choudhary RNP. [Extracted from the article]

Structural, dielectric, and electrical properties of cerium-modified strontium manganite ceramics. RETRACTED ARTICLE: Structural, dielectric and electrical properties of cerium-modified strontium manganite ceramics. [Extracted from the article]

Primary and secondary relaxation behavior of chlorobutyl elastomer nanocomposites have been studied as a function of variation in nanographite loading in the temperature range from −100°C to +100°C and in the frequency range of 100–106 Hz respectively. The effect of nanographite loadings on glass transition temperature was marginal for all the composites in the narrow range of −10°C to 10°C. The nonlinearity in tan δ and storage modulus has been explained on the concept of filler–polymer interaction and aggregation of nanographites. The effect of variation in nanographite loadings on the dielectric relaxation such as complex and real parts of impedance was distinctly visible. The electric modulus formalism has been utilized to further investigate the conductivity and relaxation phenomenon. The frequency dependence of electrical conductivity has been investigated using percolation theory. The phenomenon of percolation in the composites has been discussed based on the measured changes in electrical conductivity. The percolation threshold as studied by electrical conductivity occurred in the vicinity of 4–6 phr of nanographite loading. Cole–Cole, Nyquist plots, and Argand diagram confirm the existence of non-Debye/nonlinear relationship. Scanning electron microscopic images show agglomeration of the nanographite and formation of a continuous network structure. [ABSTRACT FROM PUBLISHER]