scholarly journals Impedance and modulus studies of Na0.9Ba0.1Nb0.9(Sn0.5Ti0.5)0.1O3 ceramic

2021 ◽  
pp. 2150013
Author(s):  
A. Oueslati ◽  
A. Aydi
Keyword(s):  
Single Phase ◽  
Equivalent Circuit Model ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Bulk Resistance ◽  
X Ray ◽  
Arrhenius Relation ◽  
Nyquist Plots ◽  
Constant Phase Elements ◽  
Modulus Studies

Polycrystalline Na[Formula: see text]Ba[Formula: see text]Nb[Formula: see text](Sn[Formula: see text]Ti[Formula: see text]O3is prepared by the solid-state reaction technique. The formation of single-phase material was confirmed by an X-ray diffraction study and it was found to be a tetragonal phase at room temperature. Nyquist plots ([Formula: see text]ˆ2 versus [Formula: see text] show that the conductivity behavior is accurately represented by an equivalent circuit model which consists of a parallel combination of bulk resistance and constant phase elements (CPE). The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law. The conductivity [Formula: see text] follows the Arrhenius relation. The modulus plots can be characterized by the empirical Kohlrausch–Williams–Watts (KWW), [Formula: see text] = exp([Formula: see text]/[Formula: see text] function and the value of the stretched exponent ([Formula: see text] is found to be almost independent of temperature. The near value of activation energies obtained from the analyses of modulus and conductivity data confirms that the transport is through an ion hopping mechanism dominated by the motion of the (O[Formula: see text] ions in the structure of the investigated material.

scholarly journals Study of multiferroic properties of Bi2Fe2WO9 ceramic for device application

2016 ◽  
Vol 06 (03) ◽  
pp. 1650023 ◽  
Author(s):  
Jyoshna Rout ◽  
R. N. P. Choudhary
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Electrical Parameters ◽  
Orthorhombic Crystal ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Universal Power Law ◽  
Phase Compound ◽  
Comprehensive Study

The Bi2Fe2WO9 ceramic was prepared using a standard solid-state reaction technique. Preliminary analysis of X-ray diffraction pattern revealed the formation of single-phase compound with orthorhombic crystal symmetry. The surface morphology of the material captured using scanning electron microscope (SEM) exhibits formation of a densely packed microstructure. Comprehensive study of dielectric properties showed two anomalies at 200[Formula: see text]C and 450[Formula: see text]C: first one may be related to magnetic whereas second one may be related to ferroelectric phase transition. The field dependent magnetic study of the material shows the existence of small remnant magnetization ([Formula: see text]) of 0.052[Formula: see text]em[Formula: see text]/g at room temperature. The existence of magneto-electric (ME) coupling coefficient along with above properties confirms multi-ferroic characteristics of the compound. Selected range temperature and frequency dependent electrical parameters (impedance, modulus, conductivity) of the compound shows that electric properties are correlated to its microstructure. Detailed studies of frequency dependence of ac conductivity suggest that the material obeys Jonscher’s universal power law.

DIELECTRIC, FERROELECTRIC, PIEZOELECTRIC AND IMPEDANCE STUDY OF LEAD-FREE CERAMIC: SrBi4Ti3.975Zr0.025O15

2012 ◽  
Vol 02 (04) ◽  
pp. 1250023 ◽  
Author(s):  
B. MAMATHA ◽  
P. SARAH
Keyword(s):  
Single Phase ◽  
Electromechanical Coupling ◽  
Xrd Analysis ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Debye Relaxation ◽  
X Ray ◽  
Resonance Frequencies ◽  
Spectroscopy Studies

Polycrystalline SrBi4Ti3.975Zr0.025O15 (SBTZ) was prepared using solid-state reaction technique. SBTZ was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis indicated the formation of a single-phase orthorhombic structure. Particle size was found using SEM. The dielectric, ferroelectric, piezoelectric, modulus and impedance spectroscopy studies on SBTZ were investigated in the frequency range 1 Hz–1 MHz from room temperature (RT) to 600°C. Piezoelectric charge and electromechanical coupling coefficients were calculated from resonance and anti-resonance frequencies. Impedance and modulus plots were used as tools to analyze the sample behavior as a function of frequency. Cole–Cole plots showed a non-Debye relaxation. Conductivity measurements were performed on SBTZ.

scholarly journals Characterization and Electrical Properties of [C6H9N2]2CuCl4 Compound

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Hamdi ◽  
A. Oueslati ◽  
I. Chaabane ◽  
F. Hlel
Keyword(s):  
Small Polaron ◽  
Equivalent Circuit Model ◽  
Scanning Calorimetry ◽  
Bulk Resistance ◽  
X Ray ◽  
Compound C ◽  
Vibrational Study ◽  
Primary Mechanism ◽  
Constant Phase Elements ◽  
Alternative Current

We report measurements of X-ray powder diffraction, vibrational study, the differential scanning calorimetry (DSC), and the electric properties of a made-up [C6H9N2]2CuCl4 sample. The alternative current (ac) conductivity of the compound [C6H9N2]2CuCl4 has been measured in the temperature range 356–398 K and the frequency range 209 Hz–5 MHz. The Cole-Cole (the imaginer part (Z′′) versus real part (Z′) of impedance complex) plots are well fitted to an equivalent circuit model which consists of a parallel combination of a bulk resistance (R) and constant phase elements (CPE). The single semicircle indicates only one primary mechanism for the electrical conduction within [C6H9N2]2CuCl4. The variation of the value of these elements with temperatures confirmed the result detected by DSC and dielectric measurements. Thus the conduction in the material is probably due to a hopping or a small polaron tunneling process.

ANALYSIS OF FLUCTUATION CONDUCTIVITY OF GRANULAR Gd1-xPrxBa2Cu3O7-δ SUPERCONDUCTOR

2010 ◽  
Vol 24 (24) ◽  
pp. 2465-2475 ◽  
Author(s):  
CRISTIANO SANTOS LOPES ◽  
LINCOLN BRUM DE LEITE GUSMÃO PINHEIRO ◽  
MARCELO DOS SANTOS ◽  
ALCIONE ROBERTO JURELO ◽  
ROSÂNGELA MENEGOTTO COSTA ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Electrical Transport ◽  
Single Phase ◽  
Transition Width ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Fluctuation Conductivity ◽  
X Ray ◽  
Zero Resistance ◽  
Resistance State

Single phase polycrystalline Gd 1-x Pr x Ba 2 Cu 3 O 7-δ (0 ≤ x ≤ 0.10) samples have been prepared by standard solid state reaction technique and characterized by SEM, X-ray diffraction and electrical transport experiments. The samples were granular and homogeneous. It was observed that the critical temperature decreases and that the transition width increases with increasing Pr doping. Systematic measurements of fluctuation conductivity are reported. Special attention is taken above the critical temperature, where Gaussian and critical regimes are observed. Below the critical temperature, on approaching the zero resistance state, our results show a power-law behavior consistent with a phase transition from a paracoherent to a coherent state of the granular array.

Phase transition in Bi8Fe6Ti3O27 multiferroic ceramics

Open Physics ◽  
2008 ◽  
Vol 6 (3) ◽  
Author(s):  
Sunanda Patri ◽  
Ram Choudhary
Keyword(s):  
Remanent Polarization ◽  
Single Phase ◽  
Microstructural Analysis ◽  
Elemental Content ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Orthorhombic Crystal ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Phase Compound

AbstractThe polycrystalline Bi8Fe6Ti3O27 compound was prepared by a high-temperature solid-state reaction technique. Preliminary structural analysis by X-ray diffraction (XRD) confirms the formation of a single-phase compound in an orthorhombic crystal system at room temperature. The elemental content of the compound was analyzed by EDAX microanalysis. Microstructural analysis by scanning electron microscopy (SEM) shows that the compound has well defined grains, which are distributed uniformly throughout the surface of the pellet sample. Detailed studies of temperature-dependent dielectric response at various frequencies show dielectric anomalies at 380, 389 and 403°C for 10 kHz, 100 kHz, and 1 MHz respectively. The hysteresis loop observed by applying an electric field of 12 kV/cm on the poled sample with smaller remanent polarization supports the existence of ferroelectricity in this material. The value of d33 of the compound was found to be 19 pC/N.

scholarly journals Interdependence between electrical and magnetic properties of polycrystalline cobalt-substituted tungsten bronze multiferroic ceramics

2018 ◽  
Vol 08 (01) ◽  
pp. 1850002 ◽  
Author(s):  
Shilpi Jindal ◽  
Sheela Devi ◽  
Ajay Vasishth ◽  
Khalid Mujasam Batoo ◽  
Gagan Kumar
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Tungsten Bronze ◽  
Ferroelectric Ceramics ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Cobalt Ions ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Text Study

Polycrystalline cobalt-substituted tungsten bronze ferroelectric ceramics with chemical composition Ba5CaTi[Formula: see text]CoXNb8O[Formula: see text] ([Formula: see text], 0.02, 0.04 and 0.08) were synthesized by solid state reaction technique. X-ray diffraction (XRD) technique was used to confirm the phase formation and it revealed the formation of single phase tetragonal structure with space group P4bm. The surface morphology of the samples was studied by using the scanning electron microscopy (SEM) technique. The dielectric properties such as dielectric constant and dielectric loss have been investigated as a function of temperature and frequency. The [Formula: see text]–[Formula: see text] and [Formula: see text]–[Formula: see text] studies confirmed the coexistent of ferroelectricity and magnetism at room temperature. The [Formula: see text]–[Formula: see text] loop study indicated an increase in the coercive field while the [Formula: see text]–[Formula: see text] study depicted a decrease in the magnetization with the incorporation of cobalt ions.

STRUCTURAL AND DIELECTRIC PROPERTIES OF Ba2Sr3SmTi3V7O30

2008 ◽  
Vol 22 (30) ◽  
pp. 2999-3005 ◽  
Author(s):  
P. S. SAHOO ◽  
S. K. PATRI ◽  
R. N. P. CHOUDHARY ◽  
A. PANIGRAHI
Keyword(s):  
Activation Energy ◽  
Single Phase ◽  
Tungsten Bronze ◽  
Polycrystalline Sample ◽  
Tangent Loss ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Phase Compound ◽  
Grain Distribution

The polycrystalline sample of Ba 2 Sr 3 SmTi 3 V 7 O 30, a member of the tungsten bronze structural family, was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction analysis suggests the formation of a single-phase compound with orthorhombic structure. Detailed studies of the dielectric constant and tangent loss as a function of frequency (100 Hz to 1 MHz) and temperature (32°–500°C) show that this compound has a diffused-type of ferroelectric phase transition at 230°C. Study of the surface morphology by SEM showed uniform grain distribution on the surface of the sample with less porosity. The activation energy, calculated from the plot of temperature dependence of AC conductivity, of the compound was found to be 0.11 eV and 0.14 eV at 500 kHz and 1 MHz respectively. The nature of the variation of conductivity and value of activation energy suggest that the conduction process is of a mixed-type.

AC Conductivity and Dielectric Relaxation Studies of La0.95Sr0.05GaO2.975 Gallate

2012 ◽  
Vol 585 ◽  
pp. 205-209
Author(s):  
Kapil Sood ◽  
K. Singh ◽  
O.P. Pandey
Keyword(s):  
Dielectric Relaxation ◽  
Equivalent Circuit Model ◽  
Solid State Reaction Method ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Nyquist Plots ◽  
Relaxation Studies ◽  
Xrd Method

La0.95Sr0.05GaO2.975 has been prepared by conventional solid state reaction method. The calcined sample has been isostatically pressed into pellets at a load of 12 kN cm-2 and then sintered at 1400 °C for 12h. The crystalline phase formation and composition has been examined by X-ray diffraction (XRD) method. Dielectric relaxation of the samples has been investigated in the steps of 25 °C in the temperature range 200-600 °C and frequency range of 1-106 Hz. The bulk and grain boundary contribution with frequency has been studied using Nyquist plots. The equivalent circuit model have been drawn which are well fitted with the plots. The activation energy has been found in the range of Ea = 0.95 eV which indicates that the prepared sample is essentially ionic conductor.

scholarly journals Effect of Nd Substitution on the Microstructural and Dielectric Properties of Polycrystalline Ca(Ti0.5Fe0.5)O3

2013 ◽  
Vol 61 (1) ◽  
pp. 125-129 ◽  
Author(s):  
MR Shah ◽  
MR Amin ◽  
AKM Akther Hossain
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Average Grain Size ◽  
Iron Titanate ◽  
Higher Temperature ◽  
Calcium Iron

Neodymium substituted calcium iron titanate having the general formula Ca1-xNdx(Ti0.5Fe0.5)O3 were prepared by the standard solid state reaction technique at relatively higher temperature (1473 K). X-ray diffraction (XRD) and optical microscopy are used to carry out the structural analysis and surface morphology, respectively. The XRD analysis confirms that all compositions are single phase orthorhombic in structure. The lattice parameters and the average grain size are found to decrease but the density to increase with the increase in Nd content. The dielectric constant (?/), dielectric loss (tan?) and ac conductivity (?ac) are studied at room temperature as a function of frequency and compositions. The room temperature ?/ is found to decrease with the increase in frequency and Nd content. On the other hand, the tan? and ?ac are observed to increase with the increase in frequency and decrease with the increase in Nd content. Dhaka Univ. J. Sci. 61(1): 125-129, 2013 (January) DOI: http://dx.doi.org/10.3329/dujs.v61i1.15113

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

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