scholarly journals Synthesis Dependent Structural Magnetic and Electrical Properties of CR-Doped Lead-Free Multiferroic AlFeO3

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 440
Author(s):  
Sharah Ali A. Aldulmani ◽  
Imen Raies ◽  
Mongi Amami ◽  
Lamia Ben Farhat
Keyword(s):  
Dielectric Response ◽  
Oxygen Vacancies ◽  
Complex Impedance ◽  
Magnetic Ordering ◽  
Dielectric Behavior ◽  
Frequency Variation ◽  
Synthesis Conditions ◽  
Co Precipitation ◽  
Conducting Species ◽  
Method Show

Polycrystalline samples AlFe0.95Cr0.05O3 synthetized by a solid state (SR) and a co-precipitation (cop) method show an orthorhombic system in space group Pc21n. It was found that, the cation distribution and magnetic ordering vary toughly on the synthesis conditions. We deployed impedance spectroscopy in studying the dielectric behavior of AlFe0.95Cr0.05O3. The significant results of this work are: for both samples, permittivity and dielectric loss are very sensitive to the temperature and frequency variation. The existence of supplementary imperfections and conducting species in AFCr5-s ceramics led to important dielectric permittivity in AFCr5-s. Values of the activation energy determined at low temperature point toward oxygen vacancies motion in slight range, however at high temperature, such a motion turns to long-range one. The dielectric response in case of AFCr5-s was assigned throw complex impedance plots to the grain as well as grain boundary. Conversely, additional individual pores similarly participate to dielectric belongings of AFCr5-cop.

Structural, magnetic and electrical characterization of Cr-doped lead-free multiferroic AlFeO3 prepared by co-precipitation and solid state method

2020 ◽  
Vol 34 (19) ◽  
pp. 2050183
Author(s):  
Mongi Amami ◽  
Lamia Ben Farhat ◽  
Samia Ben Ahmed ◽  
Safa Ezzine
Keyword(s):  
Solid State ◽  
Electrical Characterization ◽  
Magnetic Ordering ◽  
Dielectric Behavior ◽  
Frequency Variation ◽  
Small Range ◽  
Solid State Method ◽  
High Dielectric Permittivity ◽  
Co Precipitation ◽  
High Dielectric

Polycrystalline samples AlFe[Formula: see text]Cr[Formula: see text]O3 synthetized by a solid state and a co-precipitation (cop) method show an orthorhombic system in space group Pc21n. It was found that the cation distribution and magnetic ordering depend toughly on the preparation conductions. The dielectric and conductivity properties of samples were studied as function of frequency and temperature. We deployed impedance spectroscopy in studying the dielectric behavior of AlFe[Formula: see text]Cr[Formula: see text]O3. The significant results of this work are as follows: For both samples, permittivity and dielectric loss are very sensitive to temperature and frequency variation. The presence of additional effects and conducting species in AFCr5 ceramics leads to high dielectric permittivity. The activation energy values point towards the small range motion of oxygen at low-temperature and long range motion at high-temperature. The dielectric response, in case of AFCr5-s, was assigned to both grain and grain boundaries. However, additional entity pores also contribute to dielectric belongings of AFCr5-cop.

Dielectric Behavior of Mechano-chemically Synthesized [(CH3NH3)3Bi2Br9]: A Lead Free Hybrid Perovskite

2021 ◽  
Author(s):  
Swagatalaxmi Pujaru ◽  
Priyabrata Sadhukhan ◽  
Basudev Ghosh ◽  
Arup Dhara ◽  
Sachindranath Das
Keyword(s):  
Impedance Spectroscopy ◽  
Complex Impedance ◽  
Negative Temperature ◽  
Dielectric Behavior ◽  
Lead Free ◽  
Published Data ◽  
Temperature Dependent ◽  
Microstructural Parameters ◽  
Hybrid Perovskite ◽  
Refinement Method

Abstract Lead free hybrid halide perovskite (CH3NH3)3Bi2Br9 has been successfully synthesized by mechano-chemical method. The microstructure analysis by Rietveld’s refinement method revealed that the crystal belongs to trigonal system with space group P3 ̅m1. The obtained microstructural parameters are well in agreement with the previously published data. Temperature-dependent ac conductivity, impedance spectroscopy, and complex dielectric properties have been investigated in detail. The negative temperature coefficient of resistance behaviour reveals the semiconducting nature of the materials. The complex impedance spectroscopy also supports the semiconducting nature of the sample with activation energy for conduction ~0.38 eV.

Upshot of Concentration of Zirconium (IV) Oxynitrate Hexa Hydrate on Preparation and Analyses of Zirconium Oxide (ZrO2) Nanoparticles by Modified Co-Precipitation Method

2021 ◽  
Vol 21 (11) ◽  
pp. 5707-5713
Author(s):  
M. Ramachandran ◽  
R. Subadevi ◽  
P. Rajkumar ◽  
R. Muthupradeepa ◽  
R. Yuvakkumar ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Complex Impedance ◽  
Impedance Analysis ◽  
Raw Material ◽  
Precipitation Method ◽  
Zro2 Nanoparticles ◽  
Fixed Amount ◽  
Complex Impedance Analysis ◽  
Dta Analysis ◽  
Co Precipitation

In the present work, pure nanocrystalline monoclinic Zirconia (ZrO2) has been successfully synthesized and optimized by the modified co-precipitation method. The concentration of raw material has been optimized with the fixed amount of precipitation agent (Potassium hydroxide KOH). The thermal history of the precursor has been examined through TG/DTA analysis. All the samples are subjected to study the structure, fingerprints of the molecular vibrations, and morphology analyses. The representative sample has been analyzed through Transmission Electron Microscope (TEM) and X-ray Photo Electron Spectroscopy (XPS) analyses. The as-prepared sample exhibits the better crystallinity and surface morphology with lesser particle size (190 nm) when the raw material concentration is 0.2 M. The as-prepared ZrO2 filler (0, 3, 6, 9, and 12 wt.%) is spread through the enhanced polymer electrolyte P(S-MMA) (27 Wt.%)-LiClO4 (8 wt.%)-EC + PC (1;1 of 65 wt.%) complex system via solution casting method. The as-synthesized electrolyte films are examined via complex impedance analysis. P(S-MMA) (27 wt.%)-LiCIO4 (8 wt.%)-EC + PC (1 ;1 of 65 wt.%)-6 wt.% of ZrO2 shows the high ionic conductivity 2.35 × 10–3 Scm–1. Temperature-dependent ionic conductivity studies obey the non-linear behavior. The enhanced ZrO2 has been expected to enhance the other electrochemical properties of the lithium secondary battery.

Investigation on Synthesis Conditions of Silicon-Doped Hydrotalcite-Like Compounds

2013 ◽  
Vol 781-784 ◽  
pp. 239-242
Author(s):  
Lei Wang ◽  
Peng Xiao
Keyword(s):  
Silicon Content ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Accurate Data ◽  
Aged Condition ◽  
Synthesis Conditions ◽  
Silicon Doped ◽  
Major Factors ◽  
Co Precipitation ◽  
Research Analysis

In this paper, SiMgAl hydotalcite synthesis conditions were investigated using co-precipitation method, within a relatively stable pH environment of 8~9. Our research, analysis and discussion focused on the effects of major factors, such as material molar ratio ,silicon content and aged condition, on the structures of synthetic products. To achieve stable and accurate data, synthetic products were characterized by XRD and IR under the identical conditions. As shown in the results, it is suggested that the best Crystallization temperature is 70°C, molar ratio of Mg to Al is 3:1, and the best content of Silicon is 0.015mol/mol.

scholarly journals Dielectric and varistor properties of rare-earth-doped ZnO and CaCu3Ti4O12 composite ceramics

2013 ◽  
Vol 03 (01) ◽  
pp. 1350001 ◽  
Author(s):  
Huafei Lu ◽  
Yuanhua Lin ◽  
Jiancong Yuan ◽  
Cewen Nan ◽  
Kexin Chen
Keyword(s):  
Rare Earth ◽  
Sol Gel ◽  
Nonlinear Coefficient ◽  
Composite Ceramic ◽  
Dielectric Behavior ◽  
Composite Ceramics ◽  
High Dielectric Permittivity ◽  
Doped Zno ◽  
Co Precipitation ◽  
High Dielectric

To investigate the multi-functional ceramics with both high permittivity and large nonlinear coefficient, we have prepared rare-earth Tb -and- Co doped ZnO and TiO 2-rich CaCu3Ti4O12 (TCCTO) powders by chemical co-precipitation and sol–gel methods respectively, and then obtained the TCCTO/ ZnO composite ceramics, sintered at 1100°C for 3 h in air. Analyzing the composite ceramics of the microstructure and phase composition indicated that the composite ceramics were composed of the main phases of ZnO and CaCu3Ti4O12 (CCTO). Our results revealed that the TCCTO/ ZnO composite ceramics showed both high dielectric and good nonlinear electrical behaviors. The composite ceramic of TCCTO: ZnO = 0.3 exhibited a high dielectric constant of ~210(1 kHz) with a nonlinear coefficient of ~11. The dielectric behavior of TCCTO/ ZnO composite could be explained by the mixture rule. With the high dielectric permittivity and tunable varistor behaviors, the composite ceramics has a potential application for the higher voltage transportation devices.

scholarly journals Flocculation of a High-Turbidity Kaolin Suspension Using Hydrophobic Modified Quaternary Ammonium Salt Polyacrylamide

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 108 ◽  
Author(s):  
Jiangya Ma ◽  
Xue Fu ◽  
Wei Xia ◽  
Kun Fu ◽  
Yi Liao
Keyword(s):  
Solid Content ◽  
Experimental Simulation ◽  
Illumination Time ◽  
Flocculation Mechanism ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Dimethyl Ammonium ◽  
Stirring Time ◽  
High Turbidity ◽  
Method Show

In this work, a novel cationic polyacrylamide (PAMD) was synthesized by acrylamide (AM) diallyl dimethyl ammonium chloride (DMD) and dodecyl polyglucoside (DPL) under low-pressure ultraviolet (UV) initiation. The intrinsic viscosity and cationic degree of PAMD were optimized in copolymerization. The optimum synthesis conditions that affect polymerization were determined to be solid content 30%, DPL content 25%, DMD content 30%, illumination time 135 min, and pH 9. The flocculation performance of flocculant PAMD with a high cationic degree was investigated in the purification of high-turbidity water. The flocculation mechanism was correspondingly studied and summarized based on Fourier transform-infrared (FTIR) analysis. Finally, the results of an experimental simulation using the response surface method show that 98.9% supernatant transmittance was achieved under dosage 4 mg/L, fast stirring time 20 min, pH 7, and stirring speed 320 rpm.

Enhanced catalytic phenol hydroxylation by CuZnFeAl layered double hydroxides: synergistic effects of Cu+ and oxygen vacancies

2021 ◽  
Vol 45 (1) ◽  
pp. 179-188
Author(s):  
Yong Jiang ◽  
Wenlong Xu ◽  
Jinhua Liang ◽  
Jiecan Shen ◽  
Xiaomin Fu ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Oxygen Vacancies ◽  
Synergistic Effects ◽  
Phenol Oxidation ◽  
Precipitation Method ◽  
Phenol Hydroxylation ◽  
Co Precipitation ◽  
Double Hydroxides

In this work, a series of CuZnFeAl-LDH catalysts for phenol oxidation to dihydroxybenzene have been prepared through a co-precipitation method.

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