scholarly journals New mixed manganites-chromites RMn1–xCrxO3 and manganites-gallates RMn 1–xCrxO3

2021 ◽  
Vol 4 (1) ◽  
pp. 74-81
Author(s):  
V. M. Hreb ◽  
◽  
I. V. Lutsyuk ◽  
V. V. Kochubei ◽  
L. O. Vasylechko ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Perovskite Structure ◽  
Sol Gel ◽  
Nanocrystalline Powders ◽  
Structure Parameters ◽  
Synthesis Conditions ◽  
Microstructural Parameters ◽  
Orthorhombic Perovskite

Nanocrystalline powders of new mixed manganites-chromites RMn0.5Cr0.5O3 (R = Pr, Sm, Er) and manganites-gallates RMn1-xGaxO3 (R = Pr, Sm, Eu; x = 0.25, 0.5) with orthorhombic perovskite structure were obtained by sol-gel citrate route. Crytal structure parameters and microstructural parameters of the materials were established depending on the synthesis conditions. Based on the resuts obtained formation of conntinuos solid solutions RMn1-xCrxO3 in the RMnO3-RCrO3 systems and limited solid solitions in the RMnO3-RGaO3 systems were predicted.

scholarly journals Sol-Gel Combustion Synthesis, Crystal Structure and Luminescence of Cr3+ and Mn4+ Ions in Nanocrystalline SrAl4O7

Inorganics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 89
Author(s):  
Vitalii Stadnik ◽  
Vasyl Hreb ◽  
Andriy Luchechko ◽  
Yaroslav Zhydachevskyy ◽  
Andrzej Suchocki ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Sol Gel ◽  
Combustion Method ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
Dopant Content ◽  
Synthesis Conditions ◽  
Microstructural Parameters ◽  
Gel Combustion ◽  
Microscopy Techniques

A series of strontium dialuminate SrAl4O7 nanopowders with the grossite-type structure doped with chromium and manganese ions were synthesized by the combined sol–gel solution combustion method with use of two different strontium salts. The Cr3+ and Mn4+ ions concentrations were varied from 0.05 to 5 at.%. Evolution of phase composition, crystal structure, and microstructural parameters of the nanocrystalline materials depending on the synthesis conditions, temperature of thermal treatment, and dopant content were investigated by the X-ray powder diffraction and the scanning electron microscopy techniques. Photoluminescent properties of SrAl4O7 nanophosphors activated with Cr3+ and Mn4+ ions were studied at room temperature. The samples exhibit typical photoluminescence in the deep-red spectral region, corresponding to d-d transitions in Cr3+ or Mn4+ ions. The intensity of this deep-red emission is dependent on the dopant concentration and annealing temperature. Features of the formation of octahedral surroundings around Cr3+ or Mn4+ ions are discussed.

The influence of synthesis conditions on the specific surface of cerium-zirconium solid solutions

2020 ◽  
Author(s):  
Polina A. Solodovnikova ◽  
Evgenie O. Baksheev ◽  
Maxim A. Mashkovtsev ◽  
Polina A. Bereskina ◽  
Egor V. Gordeev
Keyword(s):  
Specific Surface ◽  
Solid Solutions ◽  
Synthesis Conditions

Local decomposition of solid solutions, nanostructures and optical materials with negative refractive index

2016 ◽  
Vol 30 (07) ◽  
pp. 1650088
Author(s):  
Valeriy M. Ishchuk ◽  
Vladimir Sobolev
Keyword(s):  
Refractive Index ◽  
Electric Conductivity ◽  
Solid Solutions ◽  
Lead Zirconate Titanate ◽  
Perovskite Structure ◽  
Optical Materials ◽  
Negative Refractive Index ◽  
Lead Zirconate ◽  
The State ◽  
Interphase Boundaries

In this paper, a possibility of use of the controlled decomposition of solid solutions of oxides with perovskite structure in the state of coexisting domains of the antiferroelectric (AFE) and ferroelectric (FE) phases for manufacturing materials with the negative refractive index is demonstrated. The lead zirconate titanate-based solid solutions are considered as an example of substances suitable for creation of such materials. Manufactured composites constitute a dielectric AFE matrix with a structure of conducting interphase boundaries separating domains of the FE and AFE phases. The electric conductivity of the interphase boundaries occurs as a result of the local decomposition of the solid solutions in the vicinity of these boundaries. The decomposition process and consequently the conductivity of the interphase boundaries can be controlled by means of external influences.

Structural, Magnetic and Dielectric Analysis of Higher Magnetic Mn Doped Zn-Cr Oxide Nanoparticles

2021 ◽  
Vol 9 (VI) ◽  
pp. 95-102
Author(s):  
S. D. Balsure
Keyword(s):  
Type Strain ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Xrd Analysis ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Microstructural Parameters ◽  
Auto Combustion ◽  
Mn Doped ◽  
Combustion Technique

Higher magnetic Mn doped Zn-Cr oxide nanoparticles with general compositional formula MxZn0.95-xCr0.05O have been synthesized by using sol-gel auto combustion technique. Room temperature X-ray diffraction (XRD) technique has been employed to study the structural and microstructural parameters of the as-prepared samples. XRD analysis confirms the phase purity and hexagonal wurtzite structure of all the samples. Replacement of Zn2+ ions by Mn2+ ions shifts peak positions slightly towards the lower angles which in turn expands the lattice lengths ‘a’ from 3.2487 to 3.2528 Å and ‘c’ from 5.2043 to 5.2118 Å. Crystallite size obtained from Scherrer equation was confirmed by Williamson – Hall (W-H) and size – strain plot methods (SSP). Both W-H and SSP methods reveals the tensile type strain for undoped sample and comprehensive type strain for Mn2+ doped samples. Magnetic properties were investigated by using vibrating sample magnetometer. Diluted ferromagnetic behaviour is observed for all the samples and saturation magnetization (MS) increases from 0.0514 to 0.1163 emu/gm. Two-probe technique was employed to understand the dielectric behaviour of the samples as a function of frequency. At lower frequency region, both dielectric constant () and dielectric loss tangent (tan ) shows higher values and decreases with the increasing applied frequency.

Effect of Synthesis Conditions on the Structure and Electrochemical Properties of LiNi1/2Mn1/2O2 by Sol Gel Method

2011 ◽  
Vol 399-401 ◽  
pp. 1447-1450
Author(s):  
Zhi Yong Yu ◽  
Han Xing Liu
Keyword(s):  
Electrochemical Properties ◽  
Sol Gel ◽  
Electrochemical Analysis ◽  
X Ray Diffraction ◽  
Capacity Fading ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Synthesis Conditions ◽  
A Current

The layered LiNi1/2Mn1/2O2 cathode materials were synthesized by a sol gel method. The effects of calcination temperature and time on the structural and electrochemical properties of the LiNi1/2Mn1/2O2 were investigated. The prepared samples were characterized by X-ray diffraction (XRD) and electrochemical analysis. The results revealed that the layered LiNi1/2Mn1/2O2 material could be optimal synthesized at temperature of 900°C for 10h. The sample prepared under the above conditions has the highest initial discharge capacity of 151 mAh/g and showed no dramatic capacity fading during 20 cycles between 2.5-4.5V at a current rate of 20mA/g.

scholarly journals Synthesis and Characterization of Nanocrystalline ZnO Doped with Al3+ and Ni2+ by a Sol–Gel Method Coupled with Ultrasound Irradiation

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 406 ◽  
Author(s):  
M. Robles-Águila ◽  
J. Luna-López ◽  
Álvaro Hernández de la Luz ◽  
J. Martínez-Juárez ◽  
M. Rabanal
Keyword(s):  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Ultrasound Irradiation ◽  
Morphological Properties ◽  
Nanocrystalline Powders ◽  
Metallic Ions ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Zinc oxide is one of the most important semiconducting metal oxides and one of the most promising n-type materials, but its practical use is limited because of both its high thermal conductivity and its low electrical conductivity. Numerous studies have shown that doping with metals in ZnO structures leads to the modification of the band gap energy. In this work, Al-doped ZnO, Ni-doped ZnO, and undoped ZnO nanocrystalline powders were prepared by a sol–gel method coupled with ultrasound irradiation, and the results show the influence of Al3+ and Ni2+ ions in the ZnO network. The doping concentrations in ZnO of 0.99 atom % for ZnO–Al and 0.80 atom % for ZnO–Ni were obtained by X-ray Fluorescence (XRF). X-ray Diffraction (XRD) and Raman Spectroscopy showed a decreased intensity and broadening of main peaks, indicating metallic ions. The crystallite size of the sample was decreased from 24.5 nm (ZnO) to 22.0 nm (ZnO–Al) and 21 nm (ZnO–Ni). The textural and morphological properties were analyzed via Nitrogen Adsorption (BET method) and Field Emission Scanning Electron Microscopy (FESEM).

scholarly journals Microwave-Assisted Vacuum Synthesis of TiO2 Nanocrystalline Powders in One-Pot, One-Step Procedure

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 149
Author(s):  
Enrico Paradisi ◽  
Roberto Rosa ◽  
Giovanni Baldi ◽  
Valentina Dami ◽  
Andrea Cioni ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Reaction Medium ◽  
Process Intensification ◽  
Nanocrystalline Powders ◽  
Fast Heating ◽  
One Pot ◽  
Nanoparticle Suspension ◽  
Step Procedure ◽  
One Step

A new method for fast and simple synthesis of crystalline TiO2 nanoparticles with photocatalytic activity was developed by carrying out a classic sol–gel reaction directly under vacuum. The use of microwaves for fast heating of the reaction medium further reduces synthesis times. When the solvent is completely removed by vacuum, the product is obtained in the form of a powder that can be easily redispersed in water to yield a stable nanoparticle suspension, exhibiting a comparable photocatalytic activity with respect to a commercial product. The present methodology can, therefore, be considered a process intensification procedure for the production of nanotitania.

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