Structure, electric and dielectric properties of PbFe1/3Ti1/3W1/3O3 single perovskite compound

A conventional solid-state method was used to prepare Pb(Fe1/3Ti1/3W1/3)O3 single perovskite material. The sample sintered at 900?C was studied by XRD and after Rietveld refinement the orthorhombic structure with Pbam space group was confirmed. The FTIR frequency bands corresponding to Pb-O, Ti-O, O-lattice, W- O-W and Fe-O stretching vibrations together with the XRD data also confirmed that Fe2+ and W6+ ions are incorporated in the structure and most probably substituted Ti4+ ions at the B site of the perovskite ABO3 structure. The average grain size of the perovskite ceramics, estimated from SEM micrograph, was 1 to 2 ?m. Variation of dielectric properties and AC conductivity with frequency and temperature revealed that the material had semiconducting nature and negative temperature coefficient of resistance (NTCR). The Nyquist plots were modelled with an equivalent circuit consisted of parallel capacitance, resistance and constant phase element corresponding to the grains (bulk) and grain boundaries. It was observed that grain resistance (Rb) of the sample decreases with the rise of temperature, which supports the NTCR behaviour. The semi-circular arcs of the Nyquist and Cole-Cole plots confirm the semiconducting nature of the sample.

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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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Preparation and Characterizations of Novel Near Room-Temperature Driven Fe/Sr2Bi2O5 Thermocatalyst

Materials Science Forum ◽

10.4028/www.scientific.net/msf.804.63 ◽

2014 ◽

Vol 804 ◽

pp. 63-66

Author(s):

Pei Wu ◽

Xue Gang Luo ◽

Xiao Yan Lin ◽

Ke Li

Keyword(s):

Room Temperature ◽

Negative Temperature Coefficient ◽

Removal Rate ◽

Negative Temperature ◽

X Ray Diffraction ◽

Total Removal ◽

Solid State Method ◽

X Ray ◽

Conventional Solid State Method ◽

Molar Percent

In this study, room-temperature driven thermocatalyst (Fe/Sr2Bi2O5 powder) with negative temperature coefficient resistor (NTC) characteristics was prepared by conventional solid state method at various temperatures. Fe/Sr2Bi2O5 powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy EDS. The results indicate that Fe/Sr2Bi2O5 powder was prepared and the Fe has been doped successfully in Sr2Bi2O5. The thermocatalyst powder obtained a particular and stable crystal style, meanwhile, besides, well distributed size and rough surface were also found in regard to the thermocatalyst above. On the other hand, the thermocatalyst reactions show that Fe/Sr2Bi2O5 powder has highest removal rate of degradation under the 0.75% (molar percent) content of Fe at 750 oC. The total removal rate of degradation arrives at 93.8% after 3h at 50 oC. Hence, Fe/Sr2Bi2O5 powder may be a potential thermocatalyst at room-temperature for wastewater treatment in the future.

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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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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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Low Temperature Sintering and Microwave Dielectric Properties of Zinc Titanate Ceramics for LTCC Applications

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.179 ◽

2008 ◽

Vol 368-372 ◽

pp. 179-182

Author(s):

Zong Chi Liu ◽

Dong Xiang Zhou ◽

Shu Ping Gong

Keyword(s):

Dielectric Properties ◽

Sintering Temperature ◽

Microwave Dielectric Properties ◽

Sintering Behavior ◽

Solid State Method ◽

Zinc Titanate ◽

Microwave Dielectric ◽

Conventional Solid State Method ◽

State Method ◽

Titanate Ceramics

The effects of CuO-MoO3 addition on the sintering behavior and microwave dielectric properties of ZnO-TiO2 ceramics were investigated. ZnO-TiO2 ceramics were prepared with conventional solid-state method and sintered at temperatures from 850 to 1050 °C. The sintering temperature of ZnO-TiO2 ceramics with CuO-MoO3 addition could be effectively reduced to 950 °C due to the liquid phase effects resulting from the additives. A proper amount of CuO-MoO3 addition could effectively improve the densification and microwave dielectric properties of ZnO-TiO2 ceramics. ZnO-TiO2 ceramics with 3 wt% addition sintered at 950 °C for 4 h exhibited better microwave dielectric properties as follows: εr of 26.8, a Q×f value of 16780 GHz at 5.42 GHz, and a τ f value of +34.7 ppm/°C.

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Structural, optical and dielectric properties of tellurium-based double perovskite Sr2Ni1−xZnxTeO6

RSC Advances ◽

10.1039/d1ra03662a ◽

2021 ◽

Vol 11 (50) ◽

pp. 31631-31640

Author(s):

Fatasya Izreen Hanim Alias ◽

Rozilah Rajmi ◽

Mohd Fauzi Maulud ◽

Zakiah Mohamed

Keyword(s):

Dielectric Properties ◽

Solid State ◽

Double Perovskite ◽

Solid State Method ◽

Conventional Solid State Method ◽

State Method

In this paper, Sr2Ni1−xZnxTeO6 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) double perovskite compounds were synthesised by the conventional solid-state method, and the structural, optical and dielectric properties were investigated.

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

Processing and Application of Ceramics ◽

10.2298/pac1901001d ◽

2019 ◽

Vol 13 (1) ◽

pp. 1-11 ◽

Cited By ~ 7

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.

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Preparation and Properties of ZnTiNb2O8 Microwave Dielectric Cramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.217-218.1235 ◽

2011 ◽

Vol 217-218 ◽

pp. 1235-1238 ◽

Cited By ~ 8

Author(s):

Yan Lei ◽

Yan Sheng Yin ◽

Ying Cai Liu

Keyword(s):

Single Phase ◽

Negative Temperature Coefficient ◽

Negative Temperature ◽

Particle Sizes ◽

Microwave Dielectric Ceramics ◽

Solid State Method ◽

Microwave Dielectric ◽

Dielectric Ceramics ◽

Quality Factor Q ◽

Traditional Solid State Method

The single phase of ZnTiNb2O8 ceramics was obtained at 1050 °C via traditional solid-state method. The formation of the ZnTiNb2O8 phase in the calcined powders has been investigated as a function of calcination conditions by XRD technique. Morphology and particle sizes have been determined via SEM technique. The microwave dielectric ceramics ZnTiNb2O8 which sintered at 1150°C exibit the best microwave properties: high permittivity (εr =34.2), high quality factor (Q*f = 28696 GHz), but very negative temperature coefficient of resonant frequency (τf = -75.841ppm/°C).

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Tuning the Microwave Dielectric Properties of Nd0.96Yb0.04(Mg0.5Sn0.5)O3 by Introducing Ca0.8Sr0.2TiO3

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1119.451 ◽

2015 ◽

Vol 1119 ◽

pp. 451-455

Author(s):

Yih Chien Chen ◽

Chih Hung Li ◽

Hua Xian Liu ◽

Jing Yu Fu

Keyword(s):

Dielectric Properties ◽

Sintering Temperature ◽

Microwave Dielectric Properties ◽

X Ray Diffraction ◽

Ceramic System ◽

Solid State Method ◽

X Ray ◽

Microwave Dielectric ◽

Conventional Solid State Method ◽

Diffraction Patterns

The influence of sintering temperature on the microwave dielectric properties and microstructure of the (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic system were investigated with a view to their application in microwave devices. The (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic systems were prepared using the conventional solid-state method. The X-ray diffraction patterns of the (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic system shifted to higher angle as y increased. A dielectric constant of 38.2, a quality factor (Q×f) of 53,500 GHz, and a temperature coefficient of resonant frequency of-3 ppm/°Cwere obtained when the 0.4 Nd0.96Yb0.04(Mg0.5Sn0.5)O3–0.6Ca0.8Sr0.2TiO3 ceramic system was sintered at 1600 °C for 4h.

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Electromagnetic Properties of Ca-Substituted Magnetic-Dielectric Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.130-134.1396 ◽

2011 ◽

Vol 130-134 ◽

pp. 1396-1399

Author(s):

Hui Zhong ◽

Hua Lei Wang ◽

Jie Yang ◽

Yu Shi

Keyword(s):

Grain Size ◽

Electromagnetic Properties ◽

Complex Permeability ◽

Q Factor ◽

Sintering Process ◽

Solid State Method ◽

Conventional Solid State Method ◽

Average Grain Size ◽

State Method ◽

Magnetic Dielectric

Ca-substituted magnetic-dielectric composites were prepared by the conventional solid-state method. XRD and SEM techniques are employed to investigate the phase composition and microstructure of ferrite particles. The complex permeability, capacity and impedance were measured with HP4291B and 4572A instruments, respectively, in the frequency rage from 1MHz to 1.8GHz. The results showed that a improvement of resistivity and Q factor occurs with the increasing content of CaCO3. The average grain size and dielectric loss decrease with increasing Ca-additions. It also found CaCO3 can promote the sintering process.

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