Structural and electrical properties of KCa2Nb5O15 ceramics

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Banarji Behera ◽  
Pratibindhya Nayak ◽  
Ram Choudhary
Keyword(s):  
Electrical Properties ◽  
Temperature Variation ◽  
Electrical Transport ◽  
Room Temperature ◽  
Complex Impedance ◽  
Tungsten Bronze ◽  
Transport Processes ◽  
Relaxation Processes ◽  
Orthorhombic Crystal Structure ◽  
Grain Distribution

AbstractA polycrystalline sample of KCa2Nb5O15 with tungsten bronze structure was prepared by a mixed oxide method at high temperature. A preliminary structural analysis of the compound showed an orthorhombic crystal structure at room temperature. Surface morphology of the compound shows a uniform grain distribution throughout the surface of the sample. Studies of temperature variation on dielectric response at various frequencies show that the compound has a transition temperature well above the room temperature (i.e., 105°C), which was confirmed by the polarization measurement. Electrical properties of the material have been studied using a complex impedance spectroscopy (CIS) technique in a wide temperature (31–500°C) and frequency (102–106 Hz) range that showed only bulk contribution and non-Debye type relaxation processes in the material. The activation energy of the compound (calculated from both the loss and modulus spectrum) is same, and hence the relaxation process may be attributed to the same type of charge carriers. A possible ‘hopping’ mechanism for electrical transport processes in the system is evident from the modulus analysis. A plot of dc conductivity (bulk) with temperature variation demonstrates that the compound exhibits Arrhenius type of electrical conductivity.

IMPEDANCE SPECTROSCOPY STUDY OF NaCa2Nb5O15 CERAMICS

2009 ◽  
Vol 23 (01) ◽  
pp. 97-109 ◽  
Author(s):  
BANARJI BEHERA ◽  
P. NAYAK ◽  
R. N. P. CHOUDHARY
Keyword(s):  
Electrical Transport ◽  
Complex Modulus ◽  
Complex Impedance ◽  
Tungsten Bronze ◽  
Polycrystalline Sample ◽  
Transport Processes ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Wide Range ◽  
Increasing Temperature

Polycrystalline sample of NaCa 2 Nb 5 O 15 was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray structural analysis exhibits the orthorhombic crystal structure of the compound at room temperature. Detailed dielectric studies of NaCa 2 Nb 5 O 15 over a wide range of temperature (31–500°C) and frequency (102–106 Hz) did not show any dielectric anomaly (or ferroelectric phase transition) as observed in other members of the tungsten bronze structural family. However, the low loss tangent and dielectric constant increase with increasing temperature. Complex impedance and modulus plots (at different temperature and frequency) show the existence of non-Debye type of relaxation process in the compound. Complex modulus spectrum shows only grain contribution in the compound. Electric modulus analysis suggests that a possible hopping mechanism is evident for electrical transport processes in the system. Studies of AC conductivity with frequency suggest that the material obeys Jonscher's universal power law.

SYNTHESIS AND CHARACTERIZATION OF COMPLEX FERROELECTRIC OXIDE

2012 ◽  
Vol 02 (04) ◽  
pp. 1250024 ◽  
Author(s):  
PIYUSH R. DAS ◽  
B. N. PARIDA ◽  
R. PADHEE ◽  
R. N. P. CHOUDHARY
Keyword(s):  
Temperature Dependence ◽  
Electrical Transport ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Ferroelectric Properties ◽  
Complex Impedance ◽  
Electrical Transport Properties ◽  
Arrhenius Behavior ◽  
Orthorhombic Crystal ◽  
Grain Distribution

The polycrystalline sample of Li2Pb2Pr2W2Ti4V4O30 was prepared by a solid-state reaction technique. The preparation conditions of the compound have been optimized using thermal analysis (DTA and TGA) technique. Room temperature structural analysis confirms the formation of single phase compound in orthorhombic crystal system. The surface morphology of the sample, recorded by scanning electron microscope, shows uniform grain distribution on the surface of the sample. The observation of hysteresis loop confirmed that the material has ferroelectric properties at room temperature. Electrical properties of the material were studied by complex impedance spectroscopic technique. Temperature dependence of electrical parameters (impedance, modulus, etc.) is strongly correlated to the micro-structural characteristics (bulk, grain boundary, etc.) of the sample. A typical temperature-dependent resistive characteristic of the sample (i.e., negative temperature coefficient of resistance (NTCR)) exhibits its semiconducting properties. The temperature dependence of dc conductivity shows a typical Arrhenius behavior. A signature of ionic conductivity in the system was observed in ac conductivity spectrum. The sample obeys Jonscher's universal power law. The hopping mechanism for electrical transport properties of the system with nonexponential-type conductivity relaxation was suggested from the electrical modulus analysis.

Structural, dielectric, electrical and piezoelectric properties of Ba4SrRTi3V7O30 (R=Sm, Dy) ceramics

Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Priyadarshini Sahoo ◽  
Anuradha Panigrahi ◽  
Sunanda Patri ◽  
Ram Choudhary
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Complex Impedance ◽  
Tungsten Bronze ◽  
Negative Temperature ◽  
Scanning Electron Micrographs ◽  
Polarization Study ◽  
Semiconducting Properties ◽  
Wide Range

AbstractPolycrystalline samples of Ba4SrRTi3V7O30 (R=Sm and Dy), members of the tungsten-bronze family, were prepared using a high-temperature, solid-state reaction technique and studied their electrical properties (using complex impedance spectroscopy) in a wide range of temperature (31–500°C) and frequency (1 kHz-1 MHz). Preliminary structural (XRD) analyses of these compounds show the formation of single-phase, orthorhombic structures at room temperature. The scanning electron micrographs (SEM) provided information on the quality of the samples and uniform distribution of grains over the entire surface of the samples. Detailed studies of the dielectric properties suggest that they have undergone ferroelectric-paraelectric phase transition well above the room temperatures (i.e., 432 and 355°C for R= Sm and Dy, respectively, at frequency 100 kHz). Measurements of electrical conductivity (ac and dc) as a function of temperature suggest that the compounds have semiconducting properties much above the room temperature, with negative temperature coefficient of resistance (NTCR) behavior. The existence of ferroelectricity in these compounds was confirmed from a polarization study.

IMPEDANCE SPECTROSCOPY AND MAGNETIC PROPERTIES OF AURIVILLIUS STRUCTURES

2012 ◽  
Vol 02 (03) ◽  
pp. 1250015
Author(s):  
S. K. PATRI ◽  
R. N. P. CHOUDHARY ◽  
C. RINALDI
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Complex Impedance ◽  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Layered Perovskite Structure

Bi 9-x Fe 5+x Ti 3 O 27 (x = 0-3) compounds of bismuth layered perovskite structure have been successfully prepared by solid-state reaction method. X-ray diffraction (XRD) studies revealed the orthorhombic crystal structure of all the compounds. Impedance spectroscopy has been studied to characterize the electrical properties of polycrystalline Bi 9-x Fe 5+x Ti 3 O 27 (x = 0-3) compounds. The shape of complex impedance curves inferred the contribution of bulk and grain boundary effects on the electrical properties of the compounds. Temperature dependent magnetization measurements were made from 2 K to 300 K. Narrow hysteresis loops observed at room temperature indicate antiferromagnetic behavior of the compounds.

Room temperature variation in dielectric and electrical properties of Mn doped SnO 2 nanoparticles

2017 ◽  
Vol 4 (9) ◽  
pp. 9429-9433 ◽  
Author(s):  
Azra Parveen ◽  
Syed Afzal Ahmad ◽  
Shraddha Agrawal ◽  
Ameer Azam
Keyword(s):  
Electrical Properties ◽  
Temperature Variation ◽  
Room Temperature ◽  
Mn Doped

scholarly journals The comparative study of the structural and the electrical properties of the nano spinel ferrites prepared by the soft mehanochemical synthesis

2014 ◽  
Vol 46 (2) ◽  
pp. 235-245 ◽  
Author(s):  
D.L. Sekulic ◽  
Z.Z. Lazarevic ◽  
C. Jovalekic ◽  
A. Recnik ◽  
M. Romcevic ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Complex Impedance ◽  
Spinel Ferrites ◽  
Spectroscopy Analysis ◽  
Electrical Conductivities ◽  
Increasing Temperature ◽  
The Comparative Study ◽  
Hopping Model ◽  
Impedance Spectroscopy Analysis

Nano spinel ferrites MFe2O4 (M=Ni, Mn, Zn) were obtained by soft mechanochemical synthesis in a planetary ball mill. The appropriate mixture of oxide and hydroxide powders was used as initial compounds. All of this mixture of powders was mechanically activated, uniaxial pressed and sintered at 1100?C/2h. The phase composition of the powders and sintered samples were analyzed by XRD and Raman spectroscopy. Morphologies were examined by SEM. In this study, the AC-conductivity and DC-resistivity of sintered samples of MFe2O4 (M= Ni, Mn, Zn) ferrites were measured at different frequencies and at room temperature. The values of the electrical conductivities show an increase with increasing temperature, which indicated the semiconducting behavior of the studied ferrites. The conduction phenomenon of the investigated samples could be explained on the basis of hopping model. The complex impedance spectroscopy analysis was used to study the effect of grain and grain boundary on the electrical properties of all three obtained ferrites

scholarly journals Complex Impedance Spectroscopic Properties of Ceramics

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Praveen Khatri ◽  
Banarji Behera ◽  
V. Srinivas ◽  
R. N. P. Choudhary
Keyword(s):  
Electrical Transport ◽  
Complex Impedance ◽  
Negative Temperature ◽  
Polycrystalline Sample ◽  
Spectroscopic Properties ◽  
Wide Frequency Range ◽  
Transport Processes ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Impedance Parameters

The polycrystalline sample of was prepared by a high-temperature solid-state reaction technique. The effect of temperature on impedance parameters was studied using an impedance analyzer in a wide frequency range (  Hz). The real and imaginary parts of complex impedance trace semicircles in the complex plane. The temperature-dependent plots reveal the presence of both bulk and grain boundary effects above C. The bulk resistance of the material decreases with rise in temperature. This exhibits a typical negative temperature coefficient of resistance (NTCR) behavior of the material. The modulus analysis suggests a possible hopping mechanism for electrical transport processes of the material. The nature of variation of dc conductivity suggests the Arrhenius type of electrical conductivity.

Dielectric properties of Ba3Sr2DyTi3V7O30 ceramics

Open Physics ◽  
2010 ◽  
Vol 8 (4) ◽  
Author(s):  
Priyadarshini Sahoo ◽  
Anuradha Panigrahi ◽  
Sunanda Patri ◽  
Rasm Choudhary
Keyword(s):  
Room Temperature ◽  
Paraelectric Phase ◽  
Tungsten Bronze ◽  
Polycrystalline Sample ◽  
Dielectric Anomaly ◽  
Tungsten Bronze Structure ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Oxygen Ion ◽  
Temperature Surface

AbstractA polycrystalline sample, Ba3Sr2DyTi3V7O30, with tungsten bronze structure was prepared by a mixed-oxide method at high temperature (950°C). Preliminary structural analysis of the compound showed an orthorhombic crystal structure at room temperature. Surface morphology of the compound was studied by scanning electron microscopy. The dielectric anomaly at 321°C may be attributed to the ferro-paraelectric phase transitions. This was also confirmed from the appearance of a hysteresis loop. The nature of variation of the ac conductivity and value of activation energy at different temperature regions, suggest that the conduction process is of mixed-type (i.e., ionic-polaronic and space charge generated from the oxygen ion vacancies).

scholarly journals Synthesis and electrical properties of Ag16I12P2O7

2021 ◽  
Vol 340 ◽  
pp. 01046
Author(s):  
Artem Ulihin ◽  
Olga Protazanova
Keyword(s):  
Solid State ◽  
Ionic Conductivity ◽  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Solid Electrolyte ◽  
Wide Temperature Range ◽  
Room Temperature ◽  
Complex Impedance ◽  
High Ionic Conductivity ◽  
Spectroscopy Method

Superionic solid electrolyte Ag16I12P2O7 was prepared using solid state synthesis. The ionic conductivity of this compound was studied by the complex impedance spectroscopy method in a wide temperature range. It is shown that Ag16I12P2O7 is characterized by a high ionic conductivity at room temperature, comparable to the conductivity of liquid electrolytes.

scholarly journals Effects of Sr2+ doping on the electrical properties of (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics

2015 ◽  
Vol 9 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Amrita Singh ◽  
Kamal Prasad ◽  
Ashutosh Prasad
Keyword(s):  
Electrical Properties ◽  
Cell Structure ◽  
Complex Impedance ◽  
Piezoelectric Response ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Crystallite Sizes ◽  
Grain Distribution ◽  
Diffraction Patterns ◽  
Almost All

The influence of SrTiO3 addition on the microstructure and various electrical properties of (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNTBT6) ceramics, fabricated by a conventional high temperature solid state reaction, was investigated. Analysis of X-ray diffraction patterns revealed the formation of phase pure materials with tetragonal unit cell structure, tetragonality parameter c/a in the interval from 0.9940 to 1.0063 and crystallite sizes ranging from 33-76 nm for addition of 0.2 to 1 wt.%of SrTiO3. SEMstudies indicated that Sr2+ doping led to decrease in grain size and non-homogeneity of grain distribution for higher SrTiO3 amount (>0.6 wt.%). Complex impedance, modulus, and conductivity studies indicated the presence of grains and grain boundary contribution, non-Debye type of relaxation and NTCR behaviour of the test ceramic samples. Temperature dependent real part of complex permittivity showed peaks at 475?C and the dielectric loss tangent showed peaks corresponding to 125?C and 475?C for almost all compositions. AC activation energies, computed using Arrhenius relation in the temperature range of 325-500?C for the BNTBT6 ceramic compositions having SrTiO3 concentration from 0.2 to 1.0 wt.%, were seen to have maximal values at the lowest measurement frequency. Amongst the different chosen doped BNTBT6 ceramic compositions, the composition having 0.6wt.%of SrTiO3 showed the best ferroelectric and piezoelectric response with maximum value of Pr (8.24 ?C/cm2), minimum value of Ec (5.73 kV/mm) and maximum d33 value (?46 pC/N).

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