scholarly journals Structure and dielectric properties of solid solutions Bi7−2xNd2xTi4NbO21(x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0)

2021 ◽  
pp. 2160018
Author(s):  
S. V. Zubkov
Keyword(s):  
Solid Solutions ◽  
Layer Structure ◽  
Structural Characteristics ◽  
Activation Energies ◽  
Charge Carriers ◽  
Aurivillius Phases ◽  
Lattice Space ◽  
Temperature Dependences ◽  
Temperature Ranges ◽  
Perovskite Type

The electrophysical and structural characteristics of bismuth titanate oxides of a number of phases of solid solutions of the Aurivillius phases Bi[Formula: see text]Nd[Formula: see text]Ti4NbO[Formula: see text] ([Formula: see text] = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) having a layered structure of the perovskite type have been investigated. According to the XRD data, all studied compounds are single-phase and have a mixed-layer structure of Aurivillius phases ([Formula: see text] = 2.5) with a rhombic crystal lattice (space group I2cm, [Formula: see text] = 2). A relationship has been established between changes in the chemical composition of solid solutions and orthorhombic and tetragonal distortions of perovskite-like layers. The temperature dependences of the relative permittivity [Formula: see text]/[Formula: see text](T) are measured. It was found that the change in the phase transition temperature — Curie temperature [Formula: see text] synthesized Aurivillius phases Bi[Formula: see text]Nd[Formula: see text]Ti4NbO[Formula: see text] ([Formula: see text] = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) has a close to linear dependence on the change in the parameter [Formula: see text]. The activation energies of charge carriers in different temperature ranges were calculated. It was found that three clearly defined temperature ranges with different activation energies can be distinguished, which is associated with the different nature of charge carriers in the studied solid solutions of the perovskite type. The effect of substitution of Nd[Formula: see text] ions for Bi[Formula: see text] ions is investigated.

scholarly journals Structure and dielectric properties of solid solutions Bi7Ti4+xWxNb1−2x−0.1V0.1O21 (x=0.1−0.4)

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060008
Author(s):  
S. V. Zubkov
Keyword(s):  
Solid Solutions ◽  
Single Phase ◽  
Activation Energies ◽  
Charge Carriers ◽  
Layered Oxides ◽  
Aurivillius Phases ◽  
Lattice Space ◽  
Temperature Dependences ◽  
Temperature Ranges ◽  
Perovskite Type

The structural and electrophysical characteristics of a number of solid solutions of layered oxides of the perovskite-type Bi7[Formula: see text]Wx[Formula: see text][Formula: see text][Formula: see text] ([Formula: see text]) are studied. According to X-ray powder diffraction data, all the compounds studied are single-phase and have the structure of Aurivillius phases ([Formula: see text]) with a rhombic crystal lattice (space group I2[Formula: see text]cm, [Formula: see text]). Changes in tetragonal and rhombic distortions of perovskite-like layers in compounds were considered depending on their chemical composition. The temperature dependences of the relative permittivity [Formula: see text] (T) were measured. It was shown that the Curie temperature [Formula: see text] of the perovskite-type oxides Bi7[Formula: see text]Wx[Formula: see text][Formula: see text][Formula: see text] ([Formula: see text]) linearly decreases with increasing parameter [Formula: see text]. The activation energies of charge carriers were obtained in different temperature ranges. It was found that there are three temperature regions with very different activation energies due to the different nature of the charge carriers in the studied compounds. The effect of substitution of [Formula: see text] ions by [Formula: see text] ions is investigated. It was found that for a number of compounds, the substitution of niobium ions by vanadium ions led to an increase in the dielectric constant and a decrease in the dielectric loss tangent.

scholarly journals Термоэлектрические свойства твердых растворов (CuInSe-=SUB=-2-=/SUB=-)-=SUB=-1-x-=/SUB=-(In-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=-)-=SUB=-x-=/SUB=-

2022 ◽  
Vol 56 (1) ◽  
pp. 38
Author(s):  
Ч.И. Абилов ◽  
М.Ш. Гасанова ◽  
Н.Т. Гусейнова ◽  
Э.К. Касумова
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Solid Solutions ◽  
Figure Of Merit ◽  
Charge Carriers ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Mobility Of Charge Carriers ◽  
Temperature Dependences ◽  
Thermoelectric Coefficient

The results of studying the temperature dependences of electrical conductivity, thermoelectric coefficient, Hall mobility of charge carriers, total and electronic thermal conductivity, as well as phonon thermal resistance of alloys of (CuInSe2)1-x(In2Te3)x solid solutions at x=0.005 and 0.0075 are presented. The values ​​of these parameters for certain temperatures were used to calculate the values ​​of the thermoelectric figure of merit of the indicated compositions. It turned out that as the temperature rises, the thermoelectric figure of merit tends to grow strongly, from which it can be concluded that these materials can be used in the manufacture of thermoelements.

The Ion Conducting Properties of Perovskite-Type Solid Solutions (La0.5Li0.5) [Ti1-x(M0.5Nb0.5)x]O3 (M = Al, Ga)

2006 ◽  
Vol 514-516 ◽  
pp. 407-411 ◽  
Author(s):  
Elena A. Fortalnova ◽  
Alexander V. Mosunov ◽  
Marina G. Safronenko ◽  
Nikolay U. Venskovskii ◽  
Ekaterina D. Politova
Keyword(s):  
Phase Transitions ◽  
Low Temperature ◽  
Cell Volume ◽  
Solid Solutions ◽  
Unit Cell Volume ◽  
Relaxation Effect ◽  
Unit Cell ◽  
Temperature Dependences ◽  
Ion Conducting ◽  
Perovskite Type

The influence of B-site substitution on electroconducting properties of perovskite-type solid solutions (La0.5Li0.5)[Ti1-x(M0.5Nb0.5)x]O3 with M = Al, Ga, have been studied. A decrease in the conductivity due to the unit cell contraction with increasing x in case of M = Al has been revealed. In case of Ga and Nb substitutions for Ti the unit cell volume has been found to increase with increasing x while the conductivity decreases due to the impurity phases presence. The high and low temperature anomalies on the temperature dependences of dielectric characteristic related to both the relaxation effect and phase transitions have been revealed.

scholarly journals Crystal structure and dielectric properties of layered perovskite-like solid solutions Bi3−xGdxTiNbO9 (x=0, 0.1, 0.2, 0.3) with high Curie temperature

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060002
Author(s):  
S. V. Zubkov
Keyword(s):  
Curie Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Aurivillius Phases ◽  
Lattice Space ◽  
Temperature Ranges ◽  
Curie Temperatures

The Aurivillius phases (APs) [Bi2O2][Formula: see text][[Formula: see text][Formula: see text]][Formula: see text] are well-known ferroelectrics with high Curie temperatures. High-temperature piezoceramics [Formula: see text]GdxTiNbO9(BiGdTiNb, [Formula: see text], 0.1, 0.2, 0.3) were prepared by a solid-state reaction method. The structural and electrophysical characteristics of BiGdTiNb ceramics have been studied. According to the data of powder X-ray diffraction, all the compounds are single-phase with the structures of two-layer APs ([Formula: see text]) with the orthorhombic crystal lattice (space group [Formula: see text]). The temperature dependence of the relative permittivity [Formula: see text] (T) of the compounds was measured and showed that the Curie temperature of perovskite-like oxides [Formula: see text]GdxTiNbO9 increases linearly with an increase in the substitution parameter [Formula: see text] to [Formula: see text]C. The activation energies of charge carriers have been found in different temperature ranges.

scholarly journals Электрические свойства пленок металлоорганических перовскитов

2019 ◽  
Vol 61 (2) ◽  
pp. 243
Author(s):  
А.М. Ершова ◽  
М.К. Овезов ◽  
И.П. Щербаков ◽  
А.Н. Алешин
Keyword(s):  
Phase Transitions ◽  
Electrical Properties ◽  
Orthorhombic Phase ◽  
Activation Energies ◽  
Charge Carriers ◽  
Temperature Range ◽  
Current Voltage ◽  
Temperature Dependences ◽  
Characteristic Points ◽  
Current Voltage Characteristics

AbstractThe electrical properties of the films of organometallic perovskites CH_3NH_3PbBr_3 and CH_3NH_3PbI_3 were studied. Current–voltage characteristics for the CH_3NH_3PbBr_3 and CH_3NH_3PbI_3 samples were measured in a temperature range of 300–80 K, from which the temperature dependences of resistivity ρ( T ) having characteristic points of inflection in a range of 160–240 K were determined. The activation energies of charge carriers prior to and after points of inflection were determined. It is assumed that the observed features in the temperature dependences of resistivity (temperature at the points of inflection) correlate with the temperatures of tetragonal-to-orthorhombic phase transitions for two studied organometallic perovskites (CH_3NH_3PbBr_3 and CH_3NH_3PbI_3).

Dielectric relaxation of free charge carriers in some fluorite-type solid solutions

1998 ◽  
Vol 244 ◽  
pp. 201-206 ◽  
Author(s):  
E.F. Hairetdinov ◽  
N.F. Uvarov ◽  
J.-M. Reau ◽  
P. Hagenmuller
Keyword(s):  
Dielectric Relaxation ◽  
Solid Solutions ◽  
Charge Carriers ◽  
Free Charge ◽  
Fluorite Type

scholarly journals Fabrication of Ultrathin MoS2 Nanosheets and Application on Adsorption of Organic Pollutants and Heavy Metals

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 504 ◽  
Author(s):  
Siyi Huang ◽  
Ziyun You ◽  
Yanting Jiang ◽  
Fuxiang Zhang ◽  
Kaiyang Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Electrostatic Interactions ◽  
Large Scale ◽  
Layer Structure ◽  
Structural Characteristics ◽  
Hexagonal Phase ◽  
Two Dimensional ◽  
Mos2 Nanosheets ◽  
Hybrid Strategy ◽  
Ultrathin Mos2 Nanosheets

Owing to their peculiar structural characteristics and potential applications in various fields, the ultrathin MoS2 nanosheets, a typical two-dimensional material, have attracted numerous attentions. In this paper, a hybrid strategy with combination of quenching process and liquid-based exfoliation was employed to fabricate the ultrathin MoS2 nanosheets (MoS2 NS). The obtained MoS2 NS still maintained hexagonal phase (2H-MoS2) and exhibited evident thin layer-structure (1–2 layers) with inconspicuous wrinkle. Besides, the MoS2 NS dispersion showed excellent stability (over 60 days) and high concentration (0.65 ± 0.04 mg mL−1). The MoS2 NS dispersion also displayed evident optical properties, with two characteristic peaks at 615 and 670 nm, and could be quantitatively analyzed with the absorbance at 615 nm in the range of 0.01–0.5 mg mL−1. The adsorption experiments showed that the as-prepared MoS2 NS also exhibited remarkable adsorption performance on the dyes (344.8 and 123.5 mg g−1 of qm for methylene blue and methyl orange, respectively) and heavy metals (185.2, 169.5, and 70.4 mg g−1 of qm for Cd2+, Cu2+, and Ag+). During the adsorption, the main adsorption mechanisms involved the synergism of physical hole-filling effects and electrostatic interactions. This work provided an effective way for the large-scale fabrication of the two-dimensional nanosheets of transition metal dichalcogenides (TMDs) by liquid exfoliation.

ChemInform Abstract: Nanometric Solid Solutions of the Fluorite and Perovskite Type Crystal Structures: Synthesis and Properties

ChemInform ◽  
2013 ◽  
Vol 44 (28) ◽  
pp. no-no
Author(s):  
Snezana Boskovic ◽  
Slavica Zec ◽  
Branko Matovic ◽  
Zorana Dohcevic-Mitrovic ◽  
Zoran Popovic ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Solid Solutions ◽  
Perovskite Type ◽  
Type Crystal
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