scholarly journals Sol gel and ceramic synthesis of Sr2FeMo1−xWxO6 (0 ≤ x ≤ 1) double perovskites series

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 42069-42075 ◽  
Author(s):  
M. Iranmanesh ◽  
M. Lingg ◽  
M. Stir ◽  
J. Hulliger
Keyword(s):  
Sol Gel ◽  
Double Perovskite ◽  
Double Perovskites ◽  
Ceramic Synthesis ◽  
Pure Phase

Optimization of pure phase double perovskite series via sol–gel methods.

scholarly journals Nanocrystalline Antiferromagnetic High-κ Dielectric Sr2NiMO6 (M = Te, W) with Double Perovskite Structure Type

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3996
Author(s):  
Jelena Bijelić ◽  
Dalibor Tatar ◽  
Sugato Hajra ◽  
Manisha Sahu ◽  
Sang Jae Kim ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Sol Gel ◽  
Double Perovskite ◽  
Structure Type ◽  
Nyquist Plot ◽  
Dielectric Constants ◽  
Nanocrystalline Powders ◽  
Double Perovskites ◽  
Magnetic Studies ◽  
Magnetic Ground State

Double perovskites have been extensively studied in materials chemistry due to their excellent properties and novel features attributed to the coexistence of ferro/ferri/antiferro-magnetic ground state and semiconductor band gap within the same material. Double perovskites with Sr2NiMO6 (M = Te, W) structure type have been synthesized using simple, non-toxic and costless aqueous citrate sol-gel route. The reaction yielded phase-pure nanocrystalline powders of two compounds: Sr2NiWO6 (SNWO) and Sr2NiTeO6 (SNTO). According to the Rietveld refinement of powder X-ray diffraction data at room temperature, Sr2NiWO6 is tetragonal (I4/m) and Sr2NiTeO6 is monoclinic (C12/m1), with average crystallite sizes of 49 and 77 nm, respectively. Structural studies have been additionally performed by Raman spectroscopy revealing optical phonons typical for vibrations of Te6+/W6+O6 octahedra. Both SNTO and SNWO possess high values of dielectric constants (341 and 308, respectively) with low dielectric loss (0.06 for SNWO) at a frequency of 1 kHz. These values decrease exponentially with the increase of frequency to 1000 kHz, with the dielectric constant being around 260 for both compounds and dielectric loss being 0.01 for SNWO and 0.04 for SNTO. The Nyquist plot for both samples confirms the non-Debye type of relaxation behavior and the dominance of shorter-range movement of charge carriers. Magnetic studies of both compounds revealed antiferromagnetic behavior, with Néel temperature (TN) being 57 K for SNWO and 35 K for SNTO.

Preparation of Double-Perovskites Sr2Fe1-xScxMoO6-δ Powders for the Cathode of SOEC by Sol-Gel Citrate Method

2010 ◽  
Vol 105-106 ◽  
pp. 657-659 ◽  
Author(s):  
Ben Ge ◽  
Jing Tao Ma ◽  
De Sheng Ai ◽  
Xu Ping Lin ◽  
Chang Sheng Deng
Keyword(s):  
Perovskite Structure ◽  
Ph Value ◽  
Sol Gel ◽  
Double Perovskite ◽  
Double Perovskites ◽  
Pure Perovskite Structure ◽  
Sintering Atmosphere ◽  
Citrate Method ◽  
X Ray ◽  
Air Atmosphere

Double-perovskite Sr2Fe1-xScxMoO6- (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4) powders have been synthesized by sol-gel citrate method. Initial powders were calcined in different temperature and atmosphere (air, H2(4vol%)/Ar), then analyzed by using the methods of X-ray, scanning electron microscopy (SEM), as well as thermal analysis. It is found that the formation of perovskite structure is related to the content of Sc, pH value, calcination temperature and sintering atmosphere. Especially, a pure perovskite structure almost completely formed after three hours sintering in atmosphere of H2(4vol%)/Ar. Although the formation of perovskite structure also happened in the air atmosphere, at the same time the SrMoO4 structure formed undesirably as a result of oxidization of Mo.

scholarly journals Influence of A-site Cation on Structure and Dielectric Properties in A2DyBiO6 (A=Mg, Ca, Sr, Ba) Double Perovskites

2014 ◽  
Vol 67 (2) ◽  
pp. 250 ◽  
Author(s):  
Simona Feraru ◽  
Adrian I. Borhan ◽  
Petrisor Samoila ◽  
Gigel G. Nedelcu ◽  
Alexandra R. Iordan ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Sol Gel ◽  
Double Perovskite ◽  
Combustion Method ◽  
Xrd Analysis ◽  
Double Perovskites ◽  
Structural Characterisation ◽  
Auto Combustion ◽  
Xrd Patterns ◽  
A Site

Double perovskite metal oxides with formula A2DyBiO6 (A = Mg, Ca, Sr, Ba) were synthesised by a sol–gel auto-combustion method, using citric acid as the combustion agent. The effects of A-site cation on the structure, morphology, and dielectric properties were examined. The synthesis was monitored using Fourier transform infrared spectroscopy (FTIR) to indicate the absence of organic phase. X-ray diffraction (XRD) analysis showed that the compounds have three different perovskite structures. Structural characterisation of the samples was evaluated using XRD patterns. Scanning electron microscopy showed that all samples are formed by agglomerated particles. Dielectric properties were evaluated using dielectric permittivity and dielectric losses. Cole–Cole plots show a single semicircle for all materials, indicating that the double perovskites obtained are composed of well conducting grain boundaries and poorly conducting grains.

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

Semi sol-gel synthesis and red luminescence studies of Eu3+ activated Double perovskite phosphors Bi2-xEuxMoO6 (x=0.0–0.24)

Optik ◽  
2019 ◽  
Vol 182 ◽  
pp. 565-570 ◽  
Author(s):  
B. Nagamani Naidu ◽  
K. Koteswara Rao ◽  
M.P.S. Murali Krishna
Keyword(s):  
Sol Gel ◽  
Double Perovskite ◽  
Red Luminescence ◽  
Sol Gel Synthesis

Effects of Annealing Temperature on Morphology and Dielectric Property of BiFeO3 Films

2012 ◽  
Vol 512-515 ◽  
pp. 1736-1739
Author(s):  
Li Li Zhang ◽  
Guo Qiang Tan ◽  
Meng Cheng ◽  
Hui Jun Ren ◽  
Ao Xia
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Property ◽  
Annealing Temperature ◽  
Raw Materials ◽  
Sol Gel ◽  
Frequency Range ◽  
Annealing Temperatures ◽  
Pure Phase ◽  
Lower Loss

Fe(NO3)3•9H2O and Bi(NO3)3•5H2O were used as raw materials. BiFeO3 thin films were prepared by sol-gel method. The effects of annealing temperatures on the morphology and dielectric property of the thin films were studied. XRD results show that the multi-crystal thin films with pure phase are obtained when annealed at 500°C and 550°C. But annealing at 580°C will lead to the appearance of Bi2.46Fe5O12 phase.AFM images show that as the increase of annealing temperatures the surface toughness of the thin film is decreased, but the surface undulation of the thin films is decreased gradually. Within the frequency range of 1KHz~1MHz, the dielectric constant of BiFeO3 thin films is kept over 125 and it does not change very much from 500°C to 580°C. Annealed at 550°C, the BiFeO3 thin films with the lower loss are obtained. At 1MHz, the dielectric loss is 0.12.

Preparation and Electrochemical Properties of LaMnO3 Powder as a Supercapacitor Electrode Material

2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Electrode Material ◽  
Raw Materials ◽  
Sol Gel ◽  
Galvanostatic Charge ◽  
Supercapacitor Electrode ◽  
Lanthanum Manganate ◽  
Pure Phase ◽  
Charge Discharge

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.

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