scholarly journals Enhanced electrical conductivity in Zr-Doped (La0.7Ba0.3)(Mn0.5Fe0.5)O3 solid solutions

2020 ◽  
Vol 10 (06) ◽  
pp. 2050032
Author(s):  
Yogesh Kumar ◽  
Jaswinder Pal ◽  
Parambir Singh Malhi ◽  
Rakesh Kumar
Keyword(s):  
Electrical Conductivity ◽  
Solid Solutions ◽  
Ac Conductivity ◽  
Small Polaron ◽  
Negative Temperature ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value ◽  
Jonscher’S Power Law

The perovskite ([Formula: see text][Formula: see text]([Formula: see text][Formula: see text][Formula: see text]O3, where [Formula: see text] = 0.1, 0.2 and 0.3, ceramics were synthesized by solid-state reaction method. The introductory structural studies were followed through by X-ray diffraction technique and the results have disclosed that all the samples were crystallized into an isolated phase. The Zr substitution in the resulting solid solutions increases the electrical conductivity and the maximum value of ac conductivity has been found to be [Formula: see text]118.8 S [Formula: see text] cm[Formula: see text] for [Formula: see text] = 0.3 at 200[Formula: see text]C (at 1 MHz). The frequency dependence of ac conductivity data follows Jonscher’s power law. The variation of the exponent [Formula: see text] versus temperature follows the nonoverlapping small polaron tunneling (NSPT) model. The dielectric relaxation has been observed to be of non-Debye nature for all measuring temperatures (50–200[Formula: see text]C). The impedance spectroscopy reveals that all the samples exhibit negative temperature coefficient of resistance (NTCR) behavior. The prepared samples (for [Formula: see text] > 1) are supposed to be suitable for cathode materials in SOFCs.

scholarly journals Structural, Dielectric, Magnetic and Magneto-Dielectric Properties of (1-x)BiFeO3–(x)CaTiO3 Composites

2021 ◽  
Author(s):  
Bushra Khan ◽  
Aditya Kumar ◽  
Preeti Yadav ◽  
Gulab Singh ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Ac Conductivity ◽  
Sol Gel ◽  
Negative Temperature ◽  
Tangent Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Changes ◽  
Different Temperatures ◽  
Ferromagnetic Ordering ◽  
Jonscher’S Power Law

Abstract (1-x) BiFeO3–(x) CaTiO3 [(1-x) BFO – (x) CTO, (x = 0, 0.1, 0.2 and 0.3)] composites were synthesized using sol-gel chemical rout method. X-ray diffraction investigation shows the crystal structure changes from rhombohedral to monoclinic for 0 ≤ x ≤ 0.2, and it changes to orthorhombic at x ≤ 0.3. The Field Emission Scanning Electron Microscope (FESEM) investigation confirms the the microstructure consists of randomly oriented, homogenous, and non-uniform grains. The dielectric permittivity (ε) and tangent loss (tanδ) decreases with increasing frequency and show dielectric anomalies (as a hump) at different temperatures for different compositions. The incorporation of CTO, decreases three order of leakage current (up to x = 0.2) and significantly improve the magnetization and magneto-dielectric coupling. The frequency-dependent ac conductivity obeys Jonscher’s power law with large ac conductivity dispersion for higher frequencies with increasing CTO concentration. The variations of ac conductivity with the inverse of temperature obey the Arrhenius equation and show negative temperature coefficient of resistance (NTCR) behavior. The ferromagnetic (FM) properties in BFO-CTO increases significantly with an increase of the CTO concentration. The coercive field increases with increasing CTO concentration suggesting a competition between the antiferromagnetic and ferromagnetic ordering. At room temperature, all the samples show strong magneto-dielectric coupling.

scholarly journals Structure, dielectric and electrical properties of relaxor lead-free double perovskite: Nd2NiMnO6

2019 ◽  
Vol 13 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Rutuparna Das ◽  
Ram Choudhary
Keyword(s):  
Ac Conductivity ◽  
Negative Temperature Coefficient ◽  
Complex Impedance ◽  
Double Perovskite ◽  
Negative Temperature ◽  
Solid State Reaction Method ◽  
Temperature Coefficient Of Resistance ◽  
X Ray ◽  
Impedance Data ◽  
Nyquist Plots

In this paper, dielectric relaxor, impedance, AC conductivity and electrical modulus of double perovskite Nd2NiMnO6, prepared by a solid state reaction method and sintered at 1250?C, have been reported in the wide temperature (25-150?C) and frequency (1 kHz-1MHz) ranges. From the preliminary X-ray structural analysis, it is found that the structure of the material is monoclinic. In the study of the temperature dependence of the dielectric constant, the relaxor behaviour of the material is observed. Such type of behaviour is explained by a modified Curie-Weiss and a Vogel-Fulcher law. By analysing Nyquist plots, the existence of grain and grain boundary effects is established. The non-Debye type of relaxation is investigated by the analysis of complex impedance and the modulus data. From the study of impedance data, it is found that the grain resistance is reduced with the increase in temperature indicating the existence of negative temperature coefficient of resistance (NTCR) behaviour in the material which also matches with temperature versus AC conductivity plots. From these results, it may be concluded that this compound may have extreme potential for different high temperature applications.

scholarly journals Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tatiana M. Savankova ◽  
Lev G. Akselrud ◽  
Lyudmyla I. Ardanova ◽  
Alexey V. Ignatov ◽  
Eugeni I. Get’man ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Solid Solutions ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

Thermoelectric properties and microstructure of large-grain Mg2Sn doped with Ag

2009 ◽  
Vol 1166 ◽  
Author(s):  
Haiyan Chen ◽  
Nick Savvides
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Single Phase ◽  
Silver Content ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray ◽  
Maximum Value ◽  
Vertical Bridgman ◽  
Scanning Electron

AbstractMg2Sn ingots, doped p-type by the addition of 0–1.0 at. % Ag, were prepared by the vertical Bridgman method at growth rates ∼0.1 mm/min. The crystalline quality and microstructure of ingots were analyzed by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The single-phase Mg2Sn ingots consist of highly oriented large grains. Measurements of the Hall coefficient, Seebeck coefficient α, and electrical conductivity σ in the temperature range 80–700 K were conducted to study the dependence on the silver content, and to determine the thermoelectric power factor α2σ which reached a maximum value 2.4×10-3 W m-1 K-2 at 410 K for 1.0 at.% Ag content.

scholarly journals Preparation, structure, surface and impedance analysis of Na2Zn0.5Mn0.5P2O7 ceramics

2017 ◽  
Vol 57 (3) ◽  
Author(s):  
Vilma Venckutė ◽  
Antonija Dindune ◽  
Dagnija Valdniece ◽  
Aija Krumina ◽  
Martynas Lelis ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
Impedance Analysis ◽  
Solid State Reaction Method ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Temperature Range ◽  
Two Phases

The Na2Zn0.5Mn0.5P2O7 powder was prepared by the solid state reaction method. The powder structure was studied by X-ray diffraction (XRD) in the temperature range from room temperature (RT) to 520 K. The results of XRD measurements show that the obtained Na2Zn0.5Mn0.5P2O7 is a mixture of two phases: Na2MnP2O7, which crystallizes in the triclinic space group P1, and Na2ZnP2O7, which crystallizes in the tetragonal space group P42/mmm. The chemical compositions of the powder and ceramic samples were investigated by an energy dispersive X-ray spectrometer (EDX) and X-ray fluorescence spectroscopy (XFS). The surface of ceramics was examined by X-ray photoelectron spectroscopy (XPS). The electrical conductivity and dielectric permittivity of the ceramics were investigated from RT to 700 K in the frequency range 10–109 Hz. The relaxational dispersion of electrical conductivity in the investigated frequency and temperature range was found.

Electrical and Magnetic Properties of Pb0.8La0.2Fe0.1Cr0.1Ti0.8O3

2019 ◽  
Vol 201 (1) ◽  
pp. 43-54
Author(s):  
Amrita Nayak ◽  
S. K. Patri ◽  
P. L. Deepti ◽  
B. Behera
Keyword(s):  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Polycrystalline Sample ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Phase Transition Temperatures ◽  
Different Temperatures

The dielectric spectroscopy of a new ceramic material; Pb0.8La0.2Fe0.1Cr0.1Ti0.8O3 has been studied. The compound was prepared by solid-state reaction method. The structural study from X-ray diffraction technique shows the formation of polycrystalline sample with orthorhombic crystal system at room temperature. Dielectric property of this material has been characterized in the temperature range of 25–450°C and frequency range of 100 Hz – 1 MHz respectively. The phase transition temperatures were at two different temperatures for each frequency. The nature of ac conductivity shows the negative temperature coefficient of resistance type behavior of the material.

Electrical Conductivity of NiO-Gadolinia Doped Ceria Anode Material for Intermediate Temperature Solid Oxide Fuel Cells

2017 ◽  
Vol 17 ◽  
pp. 224-236 ◽  
Author(s):  
Ajith Kumar Soman ◽  
P. Kuppusami ◽  
Arul Maximus Rabel
Keyword(s):  
Electrical Conductivity ◽  
Solid Oxide Fuel Cells ◽  
Anode Material ◽  
Solid State Reaction Method ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
Ac Impedance Spectroscopy ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Total Electrical Conductivity

In this paper, NiO-Gadolinia Doped Ceria (10 mole % Gadolinia) NiO-GDC10 composite with Nickel varying from 50 to 65 wt.% has been prepared by conventional solid state reaction method. The structural and microstructural properties have been evaluated by X-ray diffraction and scanning electron microscopy, respectively. The electrochemical behavior of the composites with varying concentration of Ni has been investigated by AC impedance spectroscopy. Both the grain and grain boundary conductivities have been determined as a function of temperature in the range of 773-973 K. The highest total electrical conductivity (σGi+σGb) have been achieved as 0.28 x10-3 Scm-1 at 973 K with activation energy of 0.40 eV for composition of GDC10 with 65 wt % of NiO (NiO-GDC-65:35 wt.%). The influence of microstructure on electrical properties of the composites has been analyzed and the conductivities have been compared with the conventional NiO-YSZ (50:50) composite in order to fabricate Ni-GDC based anode material of better performance.

Effect of La Doped on the Conductivity of the Perovskite Type PbZrO3

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Salmie Suhana Che Abdullah ◽  
Imaduddin Helmi Wan Nordin ◽  
Siti Hawa Mohamed Salleh ◽  
Takao Esaka
Keyword(s):  
Electrical Conductivity ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Emf Measurements ◽  
X Ray ◽  
Perovskite Type ◽  
La Doped ◽  
Oxide Ion ◽  
Lead Site

Electrochemical properties of Pb1-xLaxZrO3+x/2 with perovskite structure have been studied. The powdery Pb1-xLaxZrO3+x/2 has been prepared by solid-state reaction method. The X-ray diffraction analysis reveals that Pb1-xLaxZrO3+x/2 (x = 0.0-0.05) sintered at 900 ˚C was single phase structure. The electrical conductivity of the material has been investigated. By doping La at the lead site, the electrical conductivity of the Pb1-xLaxZrO3+x/2 system decreased. The undoped compound showed the highest electrical conductivity of ca. 10-3 S/cm. Electromotive Force (EMF) measurements of oxygen concentration cell confirm that the charge carrier of La doped PbZrO3 was the oxide ion.

Studies of Microstructure and Electro-Magnetic Transport Property of La0.67Ca0.33MnO3 Ceramic

2017 ◽  
Vol 373 ◽  
pp. 205-208
Author(s):  
Shou Lei Xu ◽  
Er Juan Xie ◽  
Xiu Qing Cao ◽  
Yu Yang Huang ◽  
Ding Kang Xiong ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Positron Lifetime ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Metal Insulator ◽  
X Ray ◽  
Maximum Value ◽  
The Mean ◽  
Magnetic Transport ◽  
Electro Magnetic

The positron annihilation techniques and X-ray diffraction have been used to study the microstructure of the La0.67Ca0.33MnO3 ceramics prepared by the solid-state reaction method at different sintered temperatures (T=1573K, 1623K, 1673K, 1723K, 1773K, 1823K). And the electro-magnetic transport behavior of the samples was measured by VSM and Resistivity modular on PPMS. According to these results, all samples show a perovskite structure, the ferromagnetic-paramagnetic and metal-insulator transitions occur at the transition temperature Tc and TMI, respectively, which is almost the same. For La0.67Ca0.33MnO3 sintered at 1673K, the mean positron lifetime is the largest, the maximum value of the magnetization is achieved on the magnetization-temperature curve at H=0.2mT, while the transition temperature occurs at about 244K.

Upconversion Luminescence and Temperature Sensing of InNbO4:Er3+/Yb3+ Phosphors

2021 ◽  
Vol 13 (4) ◽  
pp. 563-568
Author(s):  
Xingbang Dong ◽  
Huanjun Zhang ◽  
Yi Li ◽  
Zheng Wang ◽  
Yang Yang ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Solid State Reaction Method ◽  
Temperature Sensing ◽  
Fluorescence Intensity Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Two Photon ◽  
Maximum Value ◽  
Optical Thermometry

Er3+/Yb3+ co-doped InNbO4 phosphors were synthesized using solid state reaction method. Crystal structure was characterized using X-ray diffraction (XRD), which confirm all obtained phosphors had a monoclinic-wolframite structure and no impurity phase was introduced upon doping. Upon 980 nm excitation, upconversion (UC) emission from Er3+ ions was observed in green and red range. UC emission was obviously enhanced after co-doping Yb3+ ions and reached the maximum for 10 mol% Yb3+ ions. The relation between emission intensity and pump power was performed, revealing that the UC emission result from two-photon processes. Optical temperature sensing property was investigated by exploiting fluorescence intensity ratio (FIR) between 2H11/2 and 4S3/2 levels of Er3+ ions. Its maximum value of absolute sensitivity obtained was 0.0091 K-1, suggesting InNbO4:Er3+/Yb3+ phosphors show potential application in optical thermometry.

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