scholarly journals IMPEDANCE SPECTROSCOPY AND AC CONDUCTIVITY STUDIES OF FERROELECTRIC (K0.5Na0.5)NbO3 CERAMICS

2011 ◽  
Vol 01 (03) ◽  
pp. 351-356 ◽  
Author(s):  
P. PALEI ◽  
P. KUMAR
Keyword(s):  
Ac Conductivity ◽  
Single Phase ◽  
Perovskite Phase ◽  
Impedance Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Higher Temperature

Lead free (K0.5Na0.5)NbO3 (KNN) ceramics were prepared by conventional solid state reaction route. For single perovskite phase formation, calcination temperature was optimized at 850°C for 6 h, whereas for dense morphology the sintering of the ceramic was carried out at 1120°C for 4 h. X-ray diffraction XRD analysis confirmed the formation of single phase with orthorhombic structure at room temperature. Impedance analysis and AC conductivity studies of the KNN sample was carried out in the temperature range of 703–773 K. Impedance study showed the increase in conducting behavior at higher temperature. The temperature dependence of AC conductivity indicated that the conduction process is due to doubly ionized oxygen vacancies in the higher temperature region.

scholarly journals Effect of Process Parameter Optimization in Reducing Sintering Temperature in the Synthesis and Characterization of Ba(Zn1/3Nb2/3)O3

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
P. K. Bajpai ◽  
K. N. Singh
Keyword(s):  
Perovskite Phase ◽  
Impedance Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Microwave Dielectric ◽  
Pure Perovskite Phase ◽  
Higher Temperature ◽  
Ac Conduction

Controlling the cooling rate during calcination and sintering, phase pure perovskite Ba(Zn1/3Nb2/3)O3 has been prepared by simple solid state reaction route with density >93% at relatively low sintering of 1175°C making it compatible for microwave dielectric applications. The samples are characterized by X-ray diffraction analysis and scanning electron microscopy. The X-ray diffraction shows pure perovskite phase with cubic structure. The lattice constants were obtained a = 4.1032 Å. Detailed studies of ε′ and ε′′ show that the compound exhibits dielectric anomaly at 430°C. Material shows distributed relaxation at higher temperature. Impedance analysis revealed that the impedance is mainly due to the grains. AC conduction activation energies are estimated from Arrhenius plots, and conduction mechanism is discussed.

Synthesis of Polycrystalline LaYO3 with Different Sintering Temperature

2015 ◽  
Vol 819 ◽  
pp. 117-122 ◽  
Author(s):  
N.A. Shafiqa ◽  
M.S. Idris ◽  
C.A. Salmie Suhana ◽  
R.A.M. Osman ◽  
T.Q. Tan
Keyword(s):  
Single Phase ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Pure Phase ◽  
Perovskite Ceramic

Synthesis of LaYO3 was carried out via conventional solid state reaction method. The polycrystalline samples were sintered at temperatures in the range of 1300 °C to 1500 °C with each deviation is 50 °C. X-ray diffraction (XRD) analysis indicated that the perovskite ceramic obtained its single phase at 1500 °C with ordered monoclinic perovskite structure. The pure phase sample showed 98.79 % relative density and scanning electron micrographs also proved that the porosity of the sample reduced when sample undergo sintering.

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.

INVESTIGATIONS ON Sm- AND Nb-SUBSTITUTED PZT CERAMICS

2006 ◽  
Vol 20 (29) ◽  
pp. 1879-1882 ◽  
Author(s):  
CHANDRA PRAKASH ◽  
J. K. JUNEJA
Keyword(s):  
Dielectric Constant ◽  
Single Phase ◽  
Xrd Analysis ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Pzt Ceramics ◽  
Ceramic Method ◽  
X Ray ◽  
Niobium Doping ◽  
Constant Versus

In the present paper, we report the effect of Samarium substitution and Niobium doping on the properties of a PZT(52:48). The properties studied are: structural, dielectric and ferroelectric. The samples with chemical formula Pb 0.99 Sm 0.01 Zr 0.52 Ti 0.48 O 3 were prepared by solid-state dry ceramic method. Small amount (0.5 wt%) of Nb 2 O 5 was also added. X-ray diffraction (XRD) analysis showed formation of a single phase with tetragonal structure. Dielectric properties were studied as a function of temperature and frequency. Transition temperature, Tc, was determined from dielectric constant versus temperature plot. The material shows well-defined ferroelectric (PE) hysteresis loop.

Structure and Electrical Characteristics of BaTiO3 and Ba0.99Er0.01TiO3 Ceramics

2018 ◽  
Vol 280 ◽  
pp. 127-133 ◽  
Author(s):  
F. A. Ismail ◽  
Rozana Aina Maulat Osman ◽  
Mohd Sobri Idris ◽  
N.A.M. Ahmad Hambali
Keyword(s):  
Perovskite Phase ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Grain Sizes ◽  
Capacitance Voltage ◽  
Ion Incorporation ◽  
Voltage Breakdown

Conventional solid state reaction method was used to prepare BaTiO3 and Ba0.99Er0.01TiO3 ceramics. Influence of Er3+ ion incorporation on their structural, microstructural and electrical properties was studied. The phase pure samples were obtained when heated at 1400 °C for overnight. The tetragonal perovskite phase of BaTiO3 and Ba0.99Er0.01TiO3 was confirmed by using X-ray Diffraction (XRD) analysis which is in agreement with results obtained from Rietveld refinement analysis. The lattice parameters and unit cell volume of BaTiO3 increased when doped with Erbium. Microstructural analysis of BaTiO3 and Ba0.99Er0.01TiO3 ceramics showed that the grain sizes of BaTiO3 and Ba0.99Er0.01TiO3 significantly decreased. The dielectric properties of BaTiO3 and Ba0.99Er0.01TiO3 were investigated as a function of temperature and frequency. It revealed that the Curie temperature (TC) increased by doping Er content from 110 °C to 120 °C. Ba0.99Er0.01TiO3 exhibited the high value of dielectric constant (ε=5929) at TC of 120 °C. The capacitance-voltage characteristic revealed that the voltage breakdown for both BaTiO3 and Ba0.99Er0.01TiO3 exceeded 30 V.

Analysis of Selected Area Diffraction Patterns With Winjade

1998 ◽  
Vol 4 (S2) ◽  
pp. 342-343 ◽  
Author(s):  
S. D. Walck ◽  
P. Ruzakowski-Athey
Keyword(s):  
Single Phase ◽  
Xrd Analysis ◽  
Analysis Program ◽  
X Ray Diffraction ◽  
Program Module ◽  
Vast Number ◽  
One Dimensional ◽  
X Ray ◽  
Diffraction Patterns ◽  
Xrd Patterns

The analysis of Selected Area Diffraction (SAD) patterns that are collected from a single phase material having sufficient crystallites to provide continuous rings is relatively straightforward. However, when this condition is not met and there may be several phases present having rings of a spotty nature, the pattern is complex and can be quite difficult to analyze manually because of the vast number of discrete spots. WinJade from MDI is an X-ray diffraction (XRD) analysis program with an Electron Diffraction Program Module (EDPM) that can be used to aid in the analysis of SAD patterns. The EDPM produces Integrated Circular Density Plots (ICDP), which are one-dimensional intensity profiles plotted as a function of equivalent XRD 20 values or crystal d-spacings. These ICDP's can be overlayed with XRD patterns or with reference lines from the NIST and JCPDS crystalline databases for direct comparisons.

Pb(Zr0.52Ti0.48)O3 Ceramics Synthesized Using Planetary Ball Mill

2012 ◽  
Vol 620 ◽  
pp. 486-490
Author(s):  
Shafiza Afzan Sharif ◽  
Julie Juliewatty Mohamed ◽  
W.A.W. Yusoff
Keyword(s):  
Lead Zirconate Titanate ◽  
Ball Mill ◽  
Single Phase ◽  
Perovskite Phase ◽  
Xrd Analysis ◽  
Lead Zirconate ◽  
Planetary Ball Mill ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Pzt Ceramics

Lead zirconate titanate Pb (Zr0.52Ti0.48)O3, (PZT) ceramic was successfully prepared from the mixture of commercial PbO, TiO2and ZrO2powders using planetary ball mill at room temperature. The phase formation and microstructure of the milled powders were characterized using X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). XRD results indicated that the perovskite phase of PZT was formed from the mixture of starting materials after milling for 40 h. The grain sizes of the powders have been estimated from the SEM images to be ~200 nm. The compacted PZT samples were then sintered at 950 °C for 1 h. The samples were characterized by XRD and SEM, meanwhile the density was measured by Archimedes principle. XRD analysis on the sintered samples revealed the formation of single phase Pb (Zr0.52Ti0.48)O3ceramics while the SEM images estimated the grain size to be ~2 µm. The relative density of the obtained sintered PZT ceramics was measured to be approximately 99.93 % of the theoretical density. The results hence indicate that planetary ball mill is an effective preparatory technique to improve the sinterability of PZT ceramics.

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 Effect of Fe Substitution on the Structural, Electrical and Dielectric Properties of La0.70Ca0.30MnO3 Cathode for SOFCs

2019 ◽  
Vol 9 (1) ◽  
pp. 324-328
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
X Ray ◽  
Suitable Material ◽  
Density Values ◽  
Electrical And Dielectric Properties ◽  
Fe Substitution

Perovskite solid solutions (La0.70Ca0.30)(FexMn1-x)O3 where x = 0.01, 0.20, 0.30 and 0.40 ceramics were synthesized by solid state reaction route. The structural studies were carried by X-Ray diffraction method and the observed results have indicated that all the prepared samples were crystallized into single phase. The surface morphology was studied by Scanning Electron Microscopy and the images have revealed that grain size has increased with the increasing concentration of Fe. Archimedes principle was used to calculate the density of all the sintered samples and the density values were observed to be in increasing order. The impedance and dielectric properties have been characterized at different ranges of temperature and frequency. The value of electrical conductivity were found to be more than 100 S cm-1 , which indicate that the synthesized material is suitable material for cathode of Solid Oxide Fuel Cell.

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