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

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.

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Comprehensive investigation of structural, dielectric and local piezoelectric properties of KNN ceramics

Journal of Advanced Dielectrics ◽

10.1142/s2010135x19500164 ◽

2019 ◽

Vol 09 (02) ◽

pp. 1950016 ◽

Cited By ~ 1

Author(s):

Poonam Kumari ◽

Madan Lal ◽

Sunil Kumar ◽

Radheshyam Rai ◽

Anupinder Singh ◽

...

Keyword(s):

Negative Temperature Coefficient ◽

Piezoelectric Properties ◽

Negative Temperature ◽

Solid State Reaction Method ◽

X Ray Diffraction ◽

Temperature Coefficient Of Resistance ◽

X Ray ◽

Ceramic Samples ◽

Free Ion ◽

Diffraction Patterns

In this research paper, we utilized the traditional high-temperature solid-state reaction method to fabricate the K[Formula: see text]Na[Formula: see text]NbO3, K[Formula: see text]Na[Formula: see text]NbO3 and K[Formula: see text]Na[Formula: see text]NbO3 (abbreviated as KNN-1, KNN-2, and KNN-3, respectively) lead-free ion deficient ceramics for understanding the influence of ionic deficiency on the crystalline structure and dielectric/piezoelectric properties of the samples. X-ray diffraction patterns of these samples exhibited a perovskite tetragonal phase. Dielectric anomalies around 287∘C and 471∘C were identified as ferroelectric to ferroelectric and ferroelectric to paraelectric-transition temperatures for KNN-2 at 1[Formula: see text]kHz. It was found that the composition KNN-2 exhibit relatively high Curie temperature i.e., 471∘C. The conductivity plots confirm that the activation energies are frequency-dependent. The impedance behavior in our ceramic samples can be analyzed with the bulk/grain effect. The slope of [Formula: see text] with temperature shows negative temperature coefficient of resistance (NTCR) type behavior in proposed KNN ceramics material.

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Low temperature dielectric properties and NTCR behavior of the BaFe0.5Nb0.5O3 double perovskite ceramic

Physical Chemistry Chemical Physics ◽

10.1039/c9cp05707b ◽

2020 ◽

Vol 22 (5) ◽

pp. 2986-2998 ◽

Cited By ~ 21

Author(s):

Vijay Khopkar ◽

Balaram Sahoo

Keyword(s):

Dielectric Properties ◽

Low Temperature ◽

Temperature Coefficient ◽

Negative Temperature Coefficient ◽

Double Perovskite ◽

Negative Temperature ◽

Lead Free ◽

Temperature Coefficient Of Resistance ◽

Perovskite Ceramic

The microstructure and low-temperature dielectric properties of lead-free BaFe0.5Nb0.5O3 ceramics exhibiting a negative temperature coefficient of resistance behavior.

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Structural and dielectric properties of Ba0.95Bi0.05Ti1-xFexO3ceramics at x=0.0, 0.1 and 0.2 prepared by solid state method

Mediterranean Journal of Chemistry ◽

10.13171/mjc8319050305ng ◽

2019 ◽

Vol 8 (3) ◽

pp. 220-227

Author(s):

Najwa Gouitaa ◽

Taj-dine Lamcharfi ◽

Lamfadal Bouayad ◽

Farid Abdi ◽

Mohammed Naciri Bennani

Keyword(s):

Dielectric Properties ◽

Solid State ◽

Negative Temperature Coefficient ◽

Complex Impedance ◽

Negative Temperature ◽

Solid State Reaction Method ◽

Dielectric Measurements ◽

Solid State Method ◽

Temperature Coefficient Of Resistivity ◽

Diffuse Phase

The Ba0.95Bi0.05Ti1-xFexO3 ceramics at (x=0.0, 0.1 and 0.2) were prepared by the solid-state reaction method. The effect of iron substitution on structural and dielectric properties of Ba0.95Bi0.05TiO3 ceramic was studied. These compounds are found to crystallize in only tetragonal phase for x = 0.0 and 0.1 and the mixture of tetragonal and hexagonal phases for x = 0.2. The dielectric properties of Ba0.95Bi0.05Ti1-xFexO3 ceramics at x=0.0, 0.1 and 0.2 of Fe -doping concentration. The dielectric measurements as a function of temperature and frequency are studied and showed two diffuse phase transition and relaxation phenomena. The evolution of dielectric permittivity as a function of the frequency of undoped Ba0.95Bi0.05TiO3 show a relaxation phenomenon for which is displaced to the higher frequencies accompanied by a decrease in dielectric constant when x increase. The Complex impedance Cole-Cole plots showed a negative temperature coefficient of resistivity (NTCR) behavior of the Ba0.95Bi0.05Ti1-xFexO3 materials and increased in grain and grain boundaries resistivity. The relaxation behavior in the test materials is found to be of non-Debye type.

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

Integrated Ferroelectrics ◽

10.1080/10584587.2019.1668689 ◽

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.

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Structural and dielectric properties of Ba0.95Bi0.05Ti1-xFexO3ceramics at x=0.0, 0.1 and 0.2 prepared by solid state method

Mediterranean Journal of Chemistry ◽

10.13171/10.13171/mjc8319050305ng ◽

2019 ◽

Vol 8 (3) ◽

pp. 220

Author(s):

Najwa Gouitaa ◽

Taj-dine Lamcharfi ◽

Lamfadal Bouayad ◽

Farid Abdi ◽

Mohammed Naciri Bennani

Keyword(s):

Dielectric Properties ◽

Solid State ◽

Negative Temperature Coefficient ◽

Complex Impedance ◽

Negative Temperature ◽

Solid State Reaction Method ◽

Dielectric Measurements ◽

Solid State Method ◽

Temperature Coefficient Of Resistivity ◽

Diffuse Phase

The Ba0.95Bi0.05Ti1-xFexO3 ceramics at (x=0.0, 0.1 and 0.2) were prepared by the solid-state reaction method. The effect of iron substitution on structural and dielectric properties of Ba0.95Bi0.05TiO3 ceramic was studied. These compounds are found to crystallize in only tetragonal phase for x = 0.0 and 0.1 and the mixture of tetragonal and hexagonal phases for x = 0.2. The dielectric properties of Ba0.95Bi0.05Ti1-xFexO3 ceramics at x=0.0, 0.1 and 0.2 of Fe -doping concentration. The dielectric measurements as a function of temperature and frequency are studied and showed two diffuse phase transition and relaxation phenomena. The evolution of dielectric permittivity as a function of the frequency of undoped Ba0.95Bi0.05TiO3 show a relaxation phenomenon for which is displaced to the higher frequencies accompanied by a decrease in dielectric constant when x increase. The Complex impedance Cole-Cole plots showed a negative temperature coefficient of resistivity (NTCR) behavior of the Ba0.95Bi0.05Ti1-xFexO3 materials and increased in grain and grain boundaries resistivity. The relaxation behavior in the test materials is found to be of non-Debye type.

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Ionic conductivity and optical properties of self-activated phosphor CsYP2O7

10.21203/rs.3.rs-61216/v1 ◽

2020 ◽

Author(s):

mayssa karray ◽

A. OUESLETI ◽

K. KHIROUNI ◽

M. GARGOURI

Keyword(s):

Optical Properties ◽

Solid State ◽

Grain Boundary ◽

Negative Temperature ◽

Solid State Reaction Method ◽

Solid State Lasers ◽

Ionic Conductors ◽

X Ray ◽

Nyquist Plots ◽

Absorption Measurements

Abstract Pyrophosphates are interesting compounds as optical materials, ionic conductors, solid electrolytes, battery electrodes, solid-state lasers and active layer for sensors. In this context, the compound CsYP 2 O 7 has been synthesized by the solid-state reaction method. The X-ray powder diffraction at room temperature confirmed the phase formation of the synthesized compound in the monoclinic phase. The composition and morphology were performed by energy dispersive spectroscopy coupled with scanning electron microscope . The optical properties of the compound were studied by UV–Vis absorption spectroscopy. By direct investigation of the UV absorption measurements and using the Tauc model, we have found that the direct optical band gap is equal to 3.7eV. Two of the relaxation mechanisms were clearly identified from Nyquist plots and modulus analysis, which can be discerned to both grain and grain boundary contributions effect. The obtained results were analyzed by fitting the experimental data to an equivalent circuit model.Bulk resistance and grain boundary resistance decreased with the increase of temperature, which confirmed negative temperature coefficient of resistance behavior. The same values of activation energies obtained from the impedance (0.43 eV ) and hopping frequency (0.42 eV),prove that the transport happens through an ion hopping mechanism dominated by the motion of the Cs + cations in the structure of the CsYP 2 O 7 material. The results confirm tha the synthesized compound is suitable for catalysis and optoelectronic applications.

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CHARACTERIZATION OF LiPb2V5O15 CERAMICS USING IMPEDANCE SPECTROSCOPY

Modern Physics Letters B ◽

10.1142/s0217984909018989 ◽

2009 ◽

Vol 23 (05) ◽

pp. 755-764 ◽

Cited By ~ 2

Author(s):

P. S. DAS ◽

P. K. CHAKRABORTY ◽

BANARJI BEHERA ◽

R. N. P. CHOUDHARY

Keyword(s):

Impedance Spectroscopy ◽

Negative Temperature Coefficient ◽

Complex Impedance ◽

Negative Temperature ◽

Polycrystalline Sample ◽

Orthorhombic Crystal System ◽

Temperature Coefficient Of Resistance ◽

Orthorhombic Crystal ◽

Impedance Parameters

The polycrystalline sample of LiPb 2 V 5 O 15 was prepared by a mixed oxide method at low temperature (i.e. 550°C). Preliminary structural analysis confirmed the formation of the compound of an orthorhombic crystal system. The impedance parameters of the material were studied using complex impedance spectroscopy (CIS) in a wide temperature (i.e. 30–450°C) and frequency (i.e. 102–106 Hz) range. From the complex impedance plots, grain/grain boundary effects and relaxation phenomenon were observed above 30°C. Study of electrical conductivity suggests that the compound exhibits the negative temperature coefficient of resistance (NTCR) behavior like a semiconductor.

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

Journal of Advanced Dielectrics ◽

10.1142/s2010135x20500320 ◽

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.

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Phase Transition, Dielectric Relaxation and Impedance Spectroscopy of Perovskite xBa0.95Sr0.05Tio3-(1‒X)BiFe0.9Sm0.1O3 Ceramics

Bangladesh Journal of Physics ◽

10.3329/bjphy.v27i1.49724 ◽

2020 ◽

Vol 27 (1) ◽

pp. 23-42

Author(s):

MJ Miah ◽

SC Mazumder ◽

AKM Akther Hossain

Keyword(s):

Conduction Mechanism ◽

Negative Temperature Coefficient ◽

Boundary Effect ◽

Structural Phase ◽

Complex Impedance ◽

Negative Temperature ◽

Cubic Phase ◽

Structural Phase Transitions ◽

Impedance Data ◽

Grain Boundary Effect

Polycrystalline xBa0.95Sr0.05TiO3-(1‒x)BiFe0.9Sm0.1O3[xBST-(1‒x)BFSO] ceramics were synthesized. The structural phase transitions were studied and it was found that structure of the compound transformed from rhombohedral to cubic phase. The compound exhibited a dielectric anomaly in the vicinity of Néel temperature of BiFeO3 except for x = 0.25. Enhanced dielectric properties were noticed and this might be attributed to the reduction of oxygen vacancies. Studies of electrical conductivity over a wide temperature range showed that the ceramics behaved like a semiconductor with the negative temperature coefficient of resistance. Contribution of grains in conduction mechanism of the materials dominated and the grain resistance was found to be decreased with the increase in temperature. A Non-Debye type relaxation was seen in the material. The impedance data were re-plotted using the modulus formulae to avoid the ambiguity arising out of the presence of grain/grain boundary effect. Activation energy was found to be 0.18 to 0.33 eV in modulus study which was very close to complex impedance observation and it was implied that the charge carrier had the same energy barrier during the relaxation. Bangladesh Journal of Physics, 27(1), 23-42, June 2020

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Aging of iron manganite negative temperature coefficient thermistors

Journal of Materials Research ◽

10.1557/jmr.1998.0176 ◽

1998 ◽

Vol 13 (5) ◽

pp. 1238-1242 ◽

Cited By ~ 11

Author(s):

T. Battault ◽

R. Legros ◽

A. Rousset

Keyword(s):

Temperature Coefficient ◽

Spinel Structure ◽

Negative Temperature Coefficient ◽

Negative Temperature ◽

X Ray Diffraction ◽

X Ray ◽

Octahedral Sites ◽

Before And After ◽

Structural Equilibrium ◽

Electrical Data

“Aging,” defined as the drift of resistance with temperature after 1000 h, was investigated for iron manganite temperature coefficient thermistors. For these devices, aging is relatively large, about 10%. The cationic distributions before and after aging were determined by Mössbauer spectroscopy. These distributions explain all the x-ray diffraction and correlated electrical data. The origin of the aging observed on iron manganites thermistors has been identified. It is due to the migration of Fe3+ ions from tetrahedral to octahedral sites of the spinel structure in order to reach a structural equilibrium.

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