Synthesis and Magnetic Properties of Nanosized Cobalt Substituted Nickel Ferrites (Ni1-xCoxFe2O4) Using Egg White (Ovalbumin) by Thermal Evaporation

2009 ◽  
Vol 4 ◽  
pp. 107-116 ◽  
Author(s):  
S. Marutha Senthil ◽  
R. Jayaprakash ◽  
V.N. Singh ◽  
B.R. Mehta ◽  
G. Govindaraj
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Frequency Band ◽  
Thermal Evaporation ◽  
Average Particle Size ◽  
Low Frequency ◽  
Egg White ◽  
Synthesis Process ◽  
Nanocrystalline Phase ◽  
Average Particle

An attempt has been made to synthesize Ni1-xCoxFe2O4 by a simple technique of thermal evaporation with the help of egg white. The use of egg white (ovalbumin) in the synthesis process mainly helps to shape the particle during the reaction. The X-ray diffraction patterns reveal that the synthesized Ni1-XCoxFe2O4 ferrites are in nanocrystalline phase. The transmission electron microscopy observation confirmed that the average particle size of Ni1-xCoxFe2O4 has been varied from 7 nm to 30 nm. EDX spectrum gives account of the percentage composition of the products such as nickel, cobalt, Fe and O. Vibrating Samples Magnetometer (VSM) have been sued to study the saturation magnetization for variation of Ni substitution over CoFe2O4 and the influence of particle size in magnetic properties. Its analysis is based on the aspect of variation in coercivity with temperature. The FTIR spectra of the sample in the range 400 – 4000 cm-1 reveals the common feature of ferrites like high frequency band to the tetrahedral and low frequency band to the octahedral stretching vibrations.

MICROSTRUCTURE AND MAGNETIC PROPERTIES OF Sm2Fe17NNx−ALLOY- POWDERS AND OF BONDED ANISOTROPIC MAGNETS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 716-720
Author(s):  
B. WALL ◽  
M. KATTER ◽  
W. RODEWALD ◽  
M. VELICESCU
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Magnetic Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
Interstitial Solid Solution ◽  
Demagnetization Curve ◽  
Microstructure And Magnetic Properties

In cast Sm2Fe17 ingots minor fractions of SmFe2 and SmFe3 may occur. Nitrogenation of such alloy-powders inidicates that only Sm2Fe17 forms an interstitial solid solution whereas SmFe2 and SmFe3 decompose directly into SmN and α-Fe. From Sm2Fe17Nx alloy powders with an average particle size of about 3 μm anisotropic magnets were prepared by adding 15 wt% Zn-powder. Annealing at 390 ºC results in intrinsic coercivities > 15 kOe promoted by the formation of an unknown binary Fe8Zn92-compound. Whereas annealing at temperatures > 420 ºC leads to the formation of binary Fe3Zn7 and ternary Sm2FeZn2. By the formation of Sm2FeZn2 from Sm2Fe17Nx+Zn some α-Fe occurs inducing a step in the demagnetization curve J(H).

YVO4: RE3+(RE = Eu, Sm, Dy, Er) nanophosphors: Facile hydrothermal synthesis, microstructure, and photoluminescence

2009 ◽  
Vol 24 (10) ◽  
pp. 3050-3056 ◽  
Author(s):  
Bing Yan ◽  
Jianhua Wu
Keyword(s):  
Particle Size ◽  
Rare Earth ◽  
Electron Microscope ◽  
Hydrothermal Synthesis ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Synthesis Process ◽  
Average Particle ◽  
Sodium Vanadate ◽  
Rare Earth Nitrates

YVO4: 10%RE3+(RE = Eu, Sm, Dy, Er) nanophosphors have been synthesized by a facile modified hydrothermal technology to obtain the high purity. The key procedure for this hydrothermal process is the adding order of precursors, in which excess sodium vanadate should be added in the solution of rare earth nitrates. The microstructure (crystal phase, morphology, particle size) of these phosphors are characterized by x-ray powder diffraction, scanning electron microscope, and transmission electron microscope, which indicates that there are some cube-like crystals with tetragonal zircon structure and the average particle size is approximately 40 nm. The luminescent behaviors for the four rare earth ion-activated YVO4nanophosphors have been studied, and, for YVO4: 10%Eu3+nanophosphors in particular, it is found that a different hydrothermal process influences the phase composition, microstructure, and photoluminescence. This result suggests that the hydrothermal synthesis process (by adding sodium vanadate to the solution of rare earth nitrates) is favorable for YVO4nanophosphor to obtain pure phase, small particle size, long luminescent lifetime, and high luminescence quantum efficiency.

Minimum Particle Diameter of the Sulfur-Doped Nano-TiO2 Transparent Hydrosol at Room Temperature

2014 ◽  
Vol 587-589 ◽  
pp. 788-791
Author(s):  
Ling Li ◽  
Hua Yan Zhang ◽  
Xiao Wei Li ◽  
Zi Hao Xu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Raw Materials ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Synthesis Process ◽  
Average Particle ◽  
Hydrolysis Method ◽  
Particle Size Analyzer

Sulfur-doped nanoTiO2transparent hydrosol with an average particle size of 3.8 nm was synthesized by a novel complexation-controlled hydrolysis method at room temperature and atmospheric pressure by using TiCl4, thiourea, organic carboxylic acid, NH3H2O, D-sorbitol etc. as raw materials. The composition, phase structure, particle size, absorbance spectrum, and photocatalytic performance of samples were characterized by XRD, nanolaser particle size analyzer, ultraviolet-visible spectrophotometer. In addition, the influence of reaction conditions in the synthesis process was also studied. The results indicate that when nanoparticle doped with 0.5% S, and the reflux time was 15 min, the photocatalytic performance of sulfur-doped TiO2hydrosol was best.

Zn-doped SnO2 nanoparticles: Structural, optical, dielectric and magnetic properties

2017 ◽  
Vol 31 (30) ◽  
pp. 1750234 ◽  
Author(s):  
Zulfiqar ◽  
Yuliang Yuan ◽  
Zainab Iqbal ◽  
Jianguo Lu
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Defect Density ◽  
Sno2 Nanoparticles ◽  
Average Particle Size ◽  
Dielectric Materials ◽  
Precipitation Method ◽  
Average Particle ◽  
Zn Content ◽  
Optical Dielectric

Zn-doped SnO2 nanoparticles have been synthesized by the chemical precipitation method with the Zn contents ([Formula: see text]) of 1, 2 and 4 wt.%. The nanoparticles are crystalline in all cases, with the average particle size decreasing from 13.4 nm to 7.71 nm as the Zn concentration increases. The visible photoluminescence emission is observed in Zn-doped SnO2 nanoparticles, with larger emission intensity at elevated Zn content. The dielectric constant has a strong doping dependence, which is evidently enhanced with increasing Zn content. Magnetization measurements reveal the enhancement in saturation magnetization and remanence magnetization, while the reduction in coercive field is observed with increasing amount of Zn dopant. The variation of optical, dielectric and magnetic properties is due to the incorporation of Zn in SnO2 with smaller particle size and higher defect density. The present study clearly reveals the doping-induced ferromagnetism in Zn-doped SnO2 nanoparticles, having applications in ultrahigh dielectric materials, high frequency devices and spintronics.

scholarly journals Polysubstituted High-Entropy [LaNd](Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 Perovskites: Correlation of the Electrical and Magnetic Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1014
Author(s):  
Vladimir E. Zhivulin ◽  
Evgeniy A. Trofimov ◽  
Svetlana A. Gudkova ◽  
Igor Yu. Pashkeev ◽  
Alexander Yu. Punda ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Chemical Composition ◽  
Average Particle Size ◽  
Maximum Size ◽  
Average Particle ◽  
Ferromagnetic Cluster ◽  
High Entropy ◽  
Wide Range ◽  
Field Cooling

La-, Nd- and La/Nd-based polysubstituted high-entropy oxides (HEOs) were produced by solid-state reactions. Composition of the B-site was fixed for all samples (Cr0.2Mn0.2Fe0.2Co0.2Ni0.2) with varying of A-site cation (La, Nd and La0.5Nd0.5). Nominal chemical composition of the HEOs correlates well with initial calculated stoichiometry. All produced samples are single phase with perovskite-like structure. Average particle size is critically dependent on chemical composition. Minimal average particle size (~400 nm) was observed for the La-based sample and maximal average particle size (5.8 μm) was observed for the Nd-based sample. The values of the configurational entropy of mixing for each sample were calculated. Electrical properties were investigated in the wide range of temperatures (150–450 K) and frequencies (10−1–107 Hz). Results are discussed in terms of the variable range hopping and the small polaron hopping mechanisms. Magnetic properties were analyzed from the temperature and field dependences of the specific magnetization. The frustrated state of the spin subsystem was observed, and it can be a result of the increasing entropy state. From the Zero-Field-Cooling and Field-Cooling regimes (ZFC-FC) curves, we determine the <S> average and Smax maximum size of a ferromagnetic nanocluster in a paramagnetic matrix. The <S> average size of a ferromagnetic cluster is ~100 nm (La-CMFCNO) and ~60 nm (LN-CMFCNO). The Smax maximum size is ~210 nm (La-CMFCNO) and ~205 nm (LN-CMFCNO). For Nd-CMFCNO, spin glass state (ferromagnetic cluster lower than 30 nm) was observed due to f-d exchange at low temperatures.

Comparison of Characteristics of BaTiO3 Prepared by Different Process

2005 ◽  
Vol 475-479 ◽  
pp. 1643-1646
Author(s):  
Qing Zhi Yan ◽  
Li-Ying Zhao ◽  
Xin Tai Su ◽  
Wen Feng Zhang ◽  
Chang Chun Ge
Keyword(s):  
Particle Size ◽  
Dielectric Property ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Process ◽  
Average Particle ◽  
Oxalate Precursor ◽  
X Ray ◽  
Auto Ignition ◽  
Significant Difference

Barium titanate powder has been prepared using sol-gel auto-ignition synthesis process and was compared with two commercial high purity BaTiO3 powders prepared by precipitation from oxalate precursor and by hydrothermal synthesis. Characterization by x-ray fluorescence, XRD, field emission scanning electron microscopy, SEM and BET revealed significant difference, particularly in particle size and agglomerate structure, resulting in different microstructure and dielectric property. The sol-gel auto-ignition synthesis process yielded weakly agglomerated powder with average particle size of 50 nm. This property is favorable for sintering and dielectric property.

Preparation of Fe/SiO2 films by sputtering and their magnetic properties.

1995 ◽  
Vol 400 ◽  
Author(s):  
Tomoko Akai ◽  
Mitsuharu Tabuchi ◽  
Ryoji Funahashi ◽  
Hiroshi Yamanaka
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Particle Size ◽  
Magnetic Properties ◽  
Treatment Time ◽  
Average Particle Size ◽  
Heat Treating ◽  
Average Particle ◽  
Sio2 Films ◽  
Average Size

AbstractSiO2 thin films containing fine Fe particles were prepared by a co-sputtering method. α-Fe particles were then formed by heat-treating the film at 650°C to 700°C. The average size of the particles was controlled by changing heat-treatment time and temperature. The magnetic properties of these samples were investigated and discussed in terms of the size of the particles. It was found that the coercivity of the sample containing α-Fe particles (average particle size = 24nm) is as large as 36 Oe which is much higher than that of the bulk Fe.

scholarly journals Homogeneous Precipitation Synthesis and Magnetic Properties of Cobalt Ferrite Nanoparticles

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Zhigang Liu ◽  
Xiaodong Li ◽  
Yonghua Leng ◽  
Jingbao Lian ◽  
Shaohong Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Cobalt Ferrite ◽  
Ph Value ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Average Particle ◽  
Homogeneous Precipitation ◽  
Transmission Electron ◽  
Reaction Solution

Magnetic nanoparticles (NPs) of cobalt ferrite have been synthesized via a homogeneous precipitation route using hexamethylenetetramine (HMT) as the precipitant. The particle size, crystal structure, and magnetic properties of the synthesized particles were investigated by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The NPs are of cubic inverse spinel structure and nearly spherical shape. With the increase of oxidation time from 30 to 180 minutes in the reaction solution at90∘C, the average particle size increases from ~30 nm to ~45 nm. The as-synthesized NPs ~30 nm in size show higherMs(61.5 emu/g) and moderate Hc (945 Oe) andMr/Ms(0.45) value compared with the materials synthesized by coprecipitation method using NaOH as precipitate at high pH value.

Increased coercivity in recalcined barium ferrite–magnetite nanocomposites

2021 ◽  
Vol 112 (5) ◽  
pp. 384-390
Author(s):  
Mohammad Jafar Molaei ◽  
Abolghasem Ataie ◽  
Shahram Raygan
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Magnetic Properties ◽  
Barium Ferrite ◽  
Average Particle Size ◽  
Particle Morphology ◽  
High Energy ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray

Abstract In this research, mixtures of barium ferrite and graphite were milled in a high-energy mechanical milling machine. The effect of recalcination on the magnetic properties of the milled samples was studied. Phase analysis, phase transformations at high temperatures, particle size distribution, magnetic properties, and particle morphology were characterized by means of X-ray diffraction, hot stage X-ray diffraction, dynamic light scattering, vibrating sample magnetometry, high-resolution transmission electron microscopy, and field-emission scanning electron microscopy, respectively. A magnetic nanocomposite of BaFe12O19/Fe3O4 formed after 20 and 40 h milling. The average particle size for the 20 and 40 h milled samples reached 106 and 68 nm, respectively. Recalcination of the milled samples resulted in barium ferrite structure recovery. The decreased particle size due to the milling and subsequent recalcination results in increased coercivity values. The coercivity for the milled and calcined sample could increase more than 40% compared to as-received barium ferrite and reaches 3935 Oe for the sample calcined at 1050 °C.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

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