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).

ELECTRICAL PROPERTIES OF LiCoVO4 CERAMICS

2011 ◽  
Vol 25 (12) ◽  
pp. 1619-1628 ◽  
Author(s):  
MOTI RAM
Keyword(s):  
Electrical Properties ◽  
Complex Modulus ◽  
Cell Structure ◽  
Complex Impedance ◽  
Lattice Parameter ◽  
Conductivity Relaxation ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Compound Formation ◽  
C Complex

Solution-based chemical method was used to prepare the compound LiCoVO 4. Compound formation was checked by X-ray diffraction (XRD) study and it revealed a cubic unit cell structure with lattice parameter: a = 8.2840 (3) Å. Complex impedance result shows bulk contribution to electrical properties up to 225°C, grain boundary effects for all T ≥ 250° C , and evidence of temperature-dependent electrical relaxation phenomena in the material. The values of activation energy were determined from the Arrhenius plot of DC conductivity versus 103/T and were equal to ~0.09 eV at 50–200°C and ~0.48 eV at 200–350°C. Complex modulus study indicates non-Debye type (polydispersive) conductivity relaxation in the compound.

scholarly journals Electrical properties of Y-type hexaferrite

2018 ◽  
Vol 08 (03) ◽  
pp. 1850022 ◽  
Author(s):  
Bibhuti B. Sahu ◽  
S. K. Patri ◽  
Banarji Behera ◽  
B. Maharana
Keyword(s):  
Electrical Properties ◽  
Complex Impedance ◽  
Polycrystalline Sample ◽  
Impedance Analysis ◽  
Rhombohedral Structure ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Solid State Reaction Technique ◽  
Complex Impedance Analysis ◽  
Bulk Effect

The polycrystalline sample of Ba2Mg2Fe[Formula: see text]O[Formula: see text] was prepared by solid-state reaction technique. Room-temperature X-ray diffraction (XRD) has confirmed the formation of rhombohedral structure. The electrical properties of the sample were studied in wide ranges of temperatures and frequencies. The impedance analysis indicates the presence of bulk effect. The bulk resistance of the material decreases with rise in temperature and exhibits NTCR behavior. This compound also exhibits the temperature-dependent non-Debye type of relaxation phenomena. The presence of non-Debye type of relaxation has been confirmed by the complex impedance analysis. The variation of DC conductivity (bulk) with temperature demonstrates that the compound exhibits Arrhenius type of electrical conductivity. The activation energy of the compound is found to be 0.55[Formula: see text]eV in high-temperature region.

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.

XRD Investigations on Film Thickness and Substrate Temperature Effects of DC Magnetron Sputtered ZnO Films

2013 ◽  
Vol 845 ◽  
pp. 241-245
Author(s):  
Jian Wei Hoon ◽  
Kah Yoong Chan ◽  
Cheng Yang Low
Keyword(s):  
Film Thickness ◽  
Substrate Temperature ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Direct Current Plasma ◽  
Crystallite Sizes ◽  
Magnetron Sputter Deposition ◽  
Magnetron Sputter ◽  
Diffraction Patterns

In this paper, direct current plasma magnetron sputter deposition technique was employed to deposit zinc oxide (ZnO) films on glass substrates. The magnetron sputtering process parameters including film thickness and substrate temperature were investigated. The crystallite sizes of the ZnO films were extracted from the measured X-ray diffraction patterns. The correlation of the crystallite size of the ZnO films with the film thickness and the substrate temperature will be discussed in this paper.

Solids Formation from Synthetic Fuel Reprocessing Solutions: Characterization of Zirconium Molybdate by ICP, XRF, and Raman Microprobe Spectroscopy

1986 ◽  
Vol 40 (3) ◽  
pp. 330-336 ◽  
Author(s):  
B. S. M. Rao ◽  
E. Gantner ◽  
H. G. Müller ◽  
J. Reinhardt ◽  
D. Steinert ◽  
...  
Keyword(s):  
Raman Spectra ◽  
X Ray Diffraction ◽  
Synthetic Fuel ◽  
Precipitation Decrease ◽  
Zirconium Molybdate ◽  
Raman Microprobe ◽  
Hydrated Zirconium ◽  
Diffraction Patterns ◽  
Almost All

Raman microprobe, ICP, and XRF techniques have been applied to characterize the solids precipitated from HNO3 solutions containing Zr and Mo under different solution conditions. The saturation yields of precipitation decrease linearly—in almost all cases—with increasing acid strength, and nearly complete precipitation of Mo occurs in 3-M HNO3 solutions; ionic strength does not seem to affect the yields. Raman spectra of the microparticles indicate that hydrated zirconium molybdate is the main product, except in solutions with large excess of Mo relative to Zr. Identification of the species formed in these solutions is made by comparison of the Raman spectra with the spectra of known compounds. X-ray diffraction patterns of hydrated and thermally treated zirconium molybdate are in accord with the reported crystallographic data.

Structural and electrical properties of Cu-doped Ni–Zn nanocrystalline ferrites for MLCI applications

2017 ◽  
Vol 31 (33) ◽  
pp. 1750318 ◽  
Author(s):  
D. Venkatesh ◽  
K. V. Ramesh
Keyword(s):  
Electrical Properties ◽  
Cation Distribution ◽  
Tetrahedral Site ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Phase Spinel ◽  
Diffraction Patterns

Polycrystalline Cu substituted Ni–Zn ferrites with chemical composition Ni[Formula: see text]Zn[Formula: see text]-Cu[Formula: see text]Fe2O4 (x = 0.00 to 0.25 in steps of 0.05) have been prepared by citrate gel autocombustion method. The samples for electrical properties have been sintered at 900[Formula: see text]C for 4 h. The X-ray diffraction patterns of all samples indicate the formation of single phase spinel cubic structure. The value of lattice parameter is decreases with increasing Cu concentration. The estimated cation distribution can be derived from X-ray diffraction intensity calculations and IR spectra. The tetrahedral and octahedral bond lengths, bond angles, cation–cation and cation–anion distances were calculated by using experimental lattice parameter and oxygen positional parameters. It is observed that Cu ions are distributed in octahedral site and subsequently Ni and Fe ions in tetrahedral site. The grain size of all samples has been calculated by Scanning Electron Microscopy (SEM) images. The variations in DC electrical resistivity and dielectric constant have been explained on the basis of proposed cation distribution.

A second occurrence of lyndochite

1965 ◽  
Vol 34 (268) ◽  
pp. 237-248 ◽  
Author(s):  
J. E. T. Horne ◽  
J. R. Butler
Keyword(s):  
Heat Treatment ◽  
Rare Earth ◽  
Peak Concentration ◽  
Type Locality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Suitable Heat Treatment ◽  
Diffraction Patterns ◽  
The Many ◽  
Almost All

SummaryLyndochite from Tura dukas, 35 miles north of Nanyuki, Kenya, agrees closely with the type material from Canada in its chemical analysis, in the distribution of the rare earths, and in X-ray diffraction data for powder after heat treatment. The mineral is compared and contrasted with aeschynite. Uranium-poor euxenite is intimately associated with lyndochite at the type locality.Since its discovery over thirty-five years ago, lyndochite has remained unrecorded outside its type locality of Lyndoch Township in Ontario, Canada. Its distinctive chemical composition sets it apart from almost all other Ti-rich metamiet niobates and, despite the many analyses that have been made on rare-earth niobate-tantalates, specimens that could have been regarded as similar to or approximating to lyndochite have rarely been mentioned. Its unusual characteristics include high ThO2 (about 10%) and appreciable rare-earth oxides (about 20%) with a lanthanon assemblage showing a peak concentration of Nd (and Ce), rather than any of the heavy lanthanons. The proportions of TiO2 (about 20%) and (Nb,Ta)2O5 (about 40%) are comparable to those in numerous niobate-tantalates, but are only associated with the percentages of ThO2 and Re2O3 mentioned above in some members of the aesehynite-priorite series. The lyndochite now described is chemically very close indeed to the Canadian lyndochite, and both specimens give closely similar X-ray diffraction patterns (after suitable heat treatment) which are distinct from those of any other metamict mineral.

(1-x)(K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xBiFeO3 Lead-Free Piezoelectric Ceramics with CuO Sintering Aid

2011 ◽  
Vol 687 ◽  
pp. 228-232
Author(s):  
Yong Jie Zhao ◽  
Yu Zhen Zhao ◽  
Rong Xia Huang ◽  
Rong Zheng Liu ◽  
He Ping Zhou
Keyword(s):  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Piezoelectric Ceramics ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Mechanical Quality Factor ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Diffraction Patterns

(1-x) (K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xmolBiFeO3 (x=0, 0.002, 0.004, 0.006, 0.008) doped with 0.8mol%CuO lead-free piezoelectric ceramics were prepared by the solid state reaction technique. X-ray diffraction patterns suggested that all the ceramics presented perovskite structure. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. The ceramic (x=0.002) near room temperature exhibited excellent electrical properties (piezoelectric constant d33=172pC/N, planar electromechanical coupling factor kp=0.43, and dielectric constant =418). A relatively high mechanical quality factor (Qm=200) was also obtained in this particular composition. All these results revealed that this system might become a promising candidate for lead-free piezoelectric materials.

Structural, Electrical, and AC-Resistivity Studies of BNT-KN Piezoelectric Ceramics

2020 ◽  
Vol 557 (1) ◽  
pp. 28-42
Author(s):  
Srinivas Pattipaka ◽  
Sweety Bora ◽  
D. Pamu
Keyword(s):  
Dielectric Response ◽  
Sol Gel ◽  
Relaxor Behavior ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Critical Temperatures ◽  
Two Phase ◽  
Structure Morphology ◽  
Sol Gel Process ◽  
Diffraction Patterns

The lead-free (1 – x) Bi0.5Na0.5TiO3 – x KNbO3 (BNT-KN; x = 0 – 0.12) composite ceramics have been synthesized by a sol-gel process. Their structure, morphology, AC conductance and dielectric response were studied systematically. The X-ray diffraction patterns of BNT-KN revealed a morphotropic phase boundary between a rhombohedral and a pseudocubic structure. The temperature-dependent dielectric response of pure BNT revealed two-phase transitions at 200 °C (TR-T or Td) and 320 °C (TC). Furthermore, the critical temperatures were found to shift to lower values with increasing KN concentration. The manifested relaxor behavior was well confirmed by a modified Curie – Weiss law. The hopping conduction mechanism in BNT-KN was characterized through AC-resistivity analysis.

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