Structural, Thermal and Magnetic Analysis of Co2FeO4 Spinel Oxide Synthesized by Co-Precipitation Process

2014 ◽  
Vol 895 ◽  
pp. 287-290 ◽  
Author(s):  
Pradeep Reddy ◽  
Yesu Raja ◽  
M. Ashok
Keyword(s):  
Crystallite Size ◽  
Single Phase ◽  
Annealing Temperature ◽  
Precipitation Process ◽  
Spinel Oxide ◽  
Nano Powder ◽  
Magnetic Analysis ◽  
Phase Compound ◽  
Different Temperatures ◽  
Co Precipitation

Co2FeO4spinel oxide nano powder was synthesized by co-precipitation process. Samples were annealed at different temperatures of 500, 800 and 900oC and the phase purity were also analyzed. As-prepared sample has two spinel phases and on annealing at 900οC single phase compound formed. The crystallite size of as-prepared is found to be 11.9 nm. The crystallite size increased with increase in annealing temperature to a maximum of 17.4 nm for 900 °C. Samples were subjected to necessary characterization for finding thermal, magnetic and optical band gap.

scholarly journals Development of Radar Absorbing Nano Crystals under Thermal Irradiation

2008 ◽  
Vol 2 ◽  
pp. 91-104 ◽  
Author(s):  
Rahul Sharma ◽  
Ramesh Chandra Agarwala ◽  
Vijaya Agarwala
Keyword(s):  
Single Phase ◽  
Ostwald Ripening ◽  
Barium Hexaferrite ◽  
Uniform Structure ◽  
Precipitation Process ◽  
Vacuum Furnace ◽  
Morphological Transformation ◽  
Radar Absorbing Material ◽  
Wide Range ◽  
Co Precipitation

Single phase W-type barium hexaferrite nano crystals of radar absorbing material (RAM) i.e., BaMe2Fe16O27 (Me2+=Fe2+) were synthesized by a modified flux method that combines the controlled chemical co-precipitation process for nucleation and complete uniform growth during in-situ annealing with NaCl flux under vacuum furnace. Uniform structure morphological transformation of nano crystals from spherical to prism faces were noticed after annealing with increasing temperatures from 200 to 1200 oC for 4 h in vacuum. XRD results showed the single phase nanocrystals of BaFe18O27 with increasing crystallanity and size from 10 to 90 nm during annealing. FESEM and TEM were used to investigate the systematic growth processes of various morphologies of nano crystals. The effect of such systematic morphological transformation of nanocrystals was observed in dielectric, dynamic magnetic and refection loss (RL) properties in Kuband (12.4 -18.0 GHz). A significant increment from -15.23 dB to -43.65 dB with wide range of bandwidth in RL loss is noticed due to the symmetric morphological growth of single phase nano crystals of RAM during annealing. This process of crystal growth, morphology evolution and RL enhancement with respect to increasing temperature were also explained in terms of ostwald ripening and quantum size effect.

scholarly journals Synthesis and Catalase Mimic Activity of MnO2 Nano Powder Prepared by Hydrothermal Process

2019 ◽  
Vol 27 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Rashed T. Rasheed ◽  
Sariya D. Al-Algawi ◽  
Rosul M. N.
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Annealing Temperature ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Atomic Force ◽  
Different Temperatures ◽  
Scanning Electron

Manganese dioxide (MnO2) nanopowder has been synthesized by hydrothermal method. MnO2 was annealed at different temperatures (250, 400, 550, 700˚C). The crystal structure and surface morphology of these nanostructures were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscopy (SEM). The catalase mimic activity (catalytic activity) of MnO2 against hydrogen peroxide (H2O2) was studied by using the new method and found that 400˚C is the best annealing temperature.

Co-Ferrite (CoFe2O4): A Material with High Magnetostriction Produced by Sol-Gel Method

2011 ◽  
Vol 326 ◽  
pp. 157-164
Author(s):  
Nasir Mehmood ◽  
Roland Grössinger ◽  
Rieko Sato Turtelli ◽  
Muhammad Aamir Raza ◽  
Sohail Afzal Khan ◽  
...  
Keyword(s):  
Saturation Magnetization ◽  
Single Phase ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Xrd Pattern ◽  
Gel Method ◽  
Heat Treated ◽  
Different Temperatures ◽  
Phase Spinel

Polycrystalline Co-ferrite was produced by modified citrate gel method. Samples were afterward heat treated at different temperatures upto 1300°C. The XRD pattern shows that all samples exhibit a single phase spinel structure and improvement and sharpness in intensity of peaks with increasing annealing temperature. Measurement of hysteresis loops demonstrate that after the heat treatment a saturation magnetization of 60- 84 emu/gis obtained. Measurements of the longitudinal magnetostriction gave values between 20 ppm and 130 ppm. Magnetostriction increases gradually with increase in annealing temperature and becomes highest when the saturation magnetization values are larger.

scholarly journals Crystal structure, optical and magnetic properties of PrFeO3 nanoparticles prepared by modified co-precipitation method

2020 ◽  
Vol 14 (4) ◽  
pp. 355-361
Author(s):  
Anh Nguyen ◽  
Ngoc Nguyen ◽  
Irina Mittova ◽  
Nikolai Perov ◽  
Valentina Mittova ◽  
...  
Keyword(s):  
Particle Size ◽  
Single Phase ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Average Particle ◽  
Strong Adsorption ◽  
Different Temperatures ◽  
Paramagnetic Materials ◽  
Co Precipitation ◽  
Potential Use

In this work, PrFeO3 nanoparticles were synthesized by modified co-precipitation method and annealed at different temperatures up to 850?C. The annealed PrFeO3 nanoparticles have single phase orthorhombic structure and the average particle size of 25-30 nm. Due to the very small particle size the prepared PrFeO3 nanoparticles are capable of being used as photocatalyst materials thanks to their strong adsorption bands at 230-400 nm and 400-800 nm observed from the UV-Vis spectra. Additionally, the PrFeO3 nanoparticles are paramagnetic materials with Hc ~ 10Oe and Mr ~ 0. These findings demonstrate their potential use not only as photocatalysts, but also as magnetic materials.

scholarly journals Investigation of Magnetic and Optical Properties of Mn-Doped SnO2 at Different Annealing Temperatures

2020 ◽  
Vol 12 (4) ◽  
pp. 555-567
Author(s):  
S. Negi ◽  
A. Sharma ◽  
P. Sharma
Keyword(s):  
Optical Properties ◽  
Annealing Temperature ◽  
Systematic Investigation ◽  
Xrd Pattern ◽  
Vis Spectroscopy ◽  
Different Temperatures ◽  
Co Precipitation ◽  
Ferromagnetic Ordering ◽  
Mn Concentration ◽  
Mn Doped

In this paper, a systematic investigation has been done to study the effect of variation in annealing temperature on magnetic and optical properties of Mn-doped SnO2. Co-precipitation technique has been used to synthesize Sn1-xMnxO2 samples with low Mn concentration (2 %). Pristine SnO2 is sintered at 350 oC. Mn-doped SnO2 samples are sintered at 350, 450, 550 and 650 oC. The structures of tetragonal rutile of SnO2 and Mn-doped SnO2 have been confirmed by the XRD pattern. Typical ferromagnetic ordering has been observed for Mn-doped SnO2 samples annealed at different temperatures. However, on increasing the annealing temperature saturation magnetization as well as the coercive field decreases, indicating a crucial phase transformation from ferromagnetism to paramagnetism. UV-Vis spectroscopy shows increase in absorbance and a slight shift in the absorption edge with Mn-doping at increasing annealing temperature indicating shifting of absorption peak towards higher wavelength. Tauc’s plot has been used to find the optical band gap (Eg).

An investigation on the synthesis of nickel aluminate

2019 ◽  
Vol 48 (6) ◽  
pp. 487-492
Author(s):  
Liliya Frolova
Keyword(s):  
Electrical Conductivity ◽  
Single Phase ◽  
Molar Ratio ◽  
Precipitation Process ◽  
Complex Method ◽  
Nickel Aluminate ◽  
Content Type ◽  
Wide Range ◽  
Co Precipitation ◽  
Derivatographic Analysis

Purpose The purpose of this paper is to study the process of coprecipitation of polyhydroxocomplexes of nickel and aluminum from solutions of nickel (Ni) (II) sulfate and aluminum (Al) (III) sulfate with caustic soda and to study the conversion process to nickel aluminate and to check its properties. Design/methodology/approach For the thermodynamic analysis of the precipitation process, the software package MEDUSA was used. The dependences of the electrical conductivity, pH and residual concentrations as functions of the OH/Me ratio were obtained. Using X-ray phase analysis, spectroscopic analysis and derivatographic analysis, the properties of the products obtained were studied. The effects of OH/Me ratio and molar ratio cation of reagents on the physicochemical properties of the products were analyzed. Findings The paper deals with the results of theoretical and experimental research on the synthesis pigments of blue and green colors based on Ni-Al spinel. The influence of the molar ratio cation content on optical and color characterise of pigments were studied. Originality/value The original complex method of studying the processes of co-precipitation of cations in the form of hydroxides is proposed. pH precipitation of aluminum hydroxide and nickel are different. It is interesting to study their co-precipitation. The resulting single-phase product is a precursor of nickel aluminate over a wide range of cation ratios. The dependences of the electrical conductivity, pH and residual concentrations as functions of the OH/Me ratio were obtained.

Electrical and Magnetic Properties of (BiLi)1/2(FeV)1/2O3

2011 ◽  
Vol 110-116 ◽  
pp. 5437-5441
Author(s):  
Subrat K. Barik ◽  
Sudipta K. Bera
Keyword(s):  
Single Phase ◽  
Complex Impedance ◽  
Polycrystalline Sample ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Phase Compound ◽  
Different Temperatures

The polycrystalline sample of (BiLi) 1/2 (FeV) 1/2O3 was prepared by a high-temperature solid-state reaction technique. A preliminary X-ray structural analysis exhibited the formation of single-phase compound with an orthorhombic structure. Detailed studies of electrical properties of the compound, investigated in a wide frequency range (1kHz-1MHz) at different temperatures by complex impedance spectroscopy (CIS) technique, showed that these properties of the material are strongly dependent on frequency and temperature. Ac conductivity is found to obey the Johnscher’s law. The M-H curve shows the presence of ferromagnetism in the studied compound.

Synthesis and Properties of Superparamagnetic Fe3O4 Nanoparticles by Co-Precipitation Process

2013 ◽  
Vol 377 ◽  
pp. 173-179 ◽  
Author(s):  
Chan Yin ◽  
Xiao Yi Wei ◽  
Ji Hua Li ◽  
Fei Wang
Keyword(s):  
Particle Size ◽  
Saturation Magnetization ◽  
Single Phase ◽  
Average Particle Size ◽  
Particle Surface ◽  
Anhydrous Ethanol ◽  
Precipitation Process ◽  
Average Particle ◽  
Agglomeration Of Nanoparticles ◽  
Co Precipitation

Superparamagnetic Fe3O4nanoparticle with single phase has been synthesized successfully by a co-precipitation process. On the other hand, the effect of additive anhydrous ethanol in synthesis procedure was investigated for the magnetic properties of nanoparticles in this paper. The structure properties of synthetic Fe3O4particle were measured through XRD, FT-IR and TG-DSC devices. The characteristic peaks of Fe3O4have been observed to testify Fe3O4with single phase. The particle size and shape were observed by SEM and TEM measurements. The addition of anhydrous ethanol could enhance the dispersion of Fe3O4nanoparticles and restrain the agglomeration of nanoparticles. Therefore, the average particle size was about 18.2 nm, smaller than that of Fe3O4particles prepared without anhydrous ethanol of 24.3 nm. Correspondingly, the saturation magnetization (Ms) of Fe3O4prepared with and without anhydrous ethanol was determined to be 53.28 emu/g and 65.28 emu/g, respectively, lower than bulk magnetite particles of 90 emu/g. That is because, synthetic Fe3O4with smaller particle size obtains the higher surface curvature, which could enhance the disordered crystal orientation on the particle surface, so the saturation magnetization was decreased.

Comparative Analysis of Adding Hydrogen Peroxide or Ethanol in Preparation of Zirconia Nano-Powder by Coprecipitation Methods

2010 ◽  
Vol 434-435 ◽  
pp. 793-795
Author(s):  
Kai Jun Wang ◽  
Jin Hu ◽  
Hua Wang ◽  
Jian Liang Liu ◽  
Xiao Lan Cai ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Comparative Analysis ◽  
Ball Milling ◽  
Raw Materials ◽  
Precipitation Process ◽  
Nano Powder ◽  
Co Precipitation ◽  
Zirconia Powders

Zirconia precursor was prepared by adding hydrogen peroxide or ethanol in co-precipitation process from raw materials of ZrOC12•8H2O and ammonia, the zirconia powders were subsequently obtained by calcination of the precursor at 600°C and ball milling. Through the analyzed by TG-DTA, XRD, SEM, the results show that by adding hydrogen peroxide or ethanol in co-precipitation process can reduce the produce of agglomerate. Ethanol and hydrogen peroxide addition on zirconia by co-precipitation for different reaction results were compared and analyzed.

Preparation, morphology, crystal structure, energy gap and photoluminescence studies of Mn2+/Cr3+ doped ZnS quantum dots

2021 ◽  
Author(s):  
P.J. Binu ◽  
S. Muthukumaran
Keyword(s):  
Crystallite Size ◽  
Energy Gap ◽  
Light Emitting Diode ◽  
Precipitation Process ◽  
Cubic Phase ◽  
Xps Spectra ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Photoluminescence Studies ◽  
Co Precipitation

Abstract Mn added ZnS (Zn0.97Mn0.03S) and Mn-Cr doped ZnS (Zn0.95Mn0.03Cr0.02S) nanostructures were synthesized by co-precipitation process. X-ray diffraction analysis confirmed the cubic phase with highest intensity along (111) orientation. The shrinkage of crystallite size from 36 Å (Zn0.97Mn0.03S) to 26 Å (Zn0.95Mn0.03Cr0.02S) and the influence of Cr and Mn on morphology, optical and photoluminescence characters in ZnS were investigated. The substitution of Cr in Zn-Mn-S lattice not only diminished the crystallite size and also produced more defect associated luminescent activation centres. The presence of Zn2+, Mn2+ and Cr3+ ions in Zn-Mn-Cr-S lattice was confirmed by XPS spectra. The elevation in energy gap by Cr addition was explained by Burstein–Moss effect and reduced crystallite size. The tuning of energy gap as well crystallite size of basic ZnS nanostructure by Mn/Cr substitution encourages these materials for modern electronic applications. FTIR spectra established the occurrence of Mn/Cr in Zn-S lattice by their characteristic bondings. The inclusion of Mn /Cr provides an efficient control over modification of various emissions which suggests their applications in organic light emitting diode materials.

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