STRUCTURAL AND MAGNETIC PROPERTIES OF HEMATITE NANOCRYSTALLINE OBTAINED BY BALL MILLING

2009 ◽  
Vol 08 (03) ◽  
pp. 267-272 ◽  
Author(s):  
O. M. LEMINE ◽  
R. MSALAM ◽  
A. ALYAMANI ◽  
M. SAJIEDDINE ◽  
S. MUFTI ◽  
...  
Keyword(s):  
Rietveld Method ◽  
Magnetic Hysteresis ◽  
Average Particle Size ◽  
Hysteresis Loops ◽  
Average Particle ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Magnetic Hysteresis Loops ◽  
Structural And Magnetic Properties

α-Fe2O3 nanoparticles were obtained by a mechanical alloying of micrometer-sized powder at different milling times. Samples were characterized by X-ray powder diffraction, scanning electron microscope (SEM), Mössbauer spectrometry, and vibrating sample magnetometer (VSM). A qualitative and quantitative phase analyses using the Rietveld method have been performed based on the XRD data. The results did not reveal any phase change during the milling. The average particle size decreases with a prolongation of milling times, while the lattice parameters, unit cell volume, and microstrain increase. Mössbauer measurement shows that there are two components, one nanometric and other micrometric. The magnetic hysteresis loops shows that the samples are typical of ferromagnet with superparamagnetic fraction in the material.

Сrystalline structure and dielectric properties of ceramic materials based on AgNbO3

2020 ◽  
Vol 63 (7) ◽  
pp. 75-78
Author(s):  
Polina A. Bezborodova ◽  
◽  
Elena M. Filonenko ◽  
Kseniya R. Erager ◽  
Anatoly V. Butakov ◽  
...  
Keyword(s):  
Rietveld Method ◽  
Average Particle Size ◽  
Ceramic Materials ◽  
Analysis Data ◽  
Molar Ratio ◽  
Average Particle ◽  
Dielectric Parameters ◽  
Low Frequencies ◽  
X Ray ◽  
Substitution Degree

Using the data of qualitative X-ray phase analysis, it was shown that in a wide concentration range at 1223 K compounds based on silver niobate are formed in the condition of the heterovalent substitution of tungsten(VI) ions for niobium(V) ions. These compounds are isomorphic to a perovskite-type structure. Microprobe analysis data allows to determine the homogeneity of the analyzed samples and the correspondence of their experimental compositions to the theoretical ones for the formula Ag1-xNb1-xWxO3. Using the data of X-ray diffraction analysis (Rietveld method) in the Crystallography Data Analysis Software – GSAS, the crystal structure of the obtained compounds was refined. The surface morphology of samples having been obtained at 1373 K was investigated by scanning electron microscopy (SEM). It was shown that with an increase of Nb5+ to W6+ substitution degree for Ag1-xNb1-xWxO3 ceramic samples in the range of the (0.2≤x≤0.8) molar ratio, the average particle size for the studied compositions grows from 1.3 to 5.2 μm, respectively. For the obtained ceramic compounds based on silver niobate with a perovskite-like structure (tetragonal distortion), the temperature-frequency dependences of dielectric parameters in the range 300-900 K were studied. It was found that samples slowly cooled from 1373 K are characterized by low values of (ε ~ 10) and loss (tgδ ~ 0.004 at f = 1 kHz) at room temperature. The ceramics obtained are characterized by relatively high values of dielectric permittivity ε at low frequencies and/or high temperatures. The dielectric parameters of the obtained ceramics are similar to the characteristics of so-called "colossal" dielectric constant materials. The revealed features of the dielectric characteristics of quenched ceramics apparently result from Maxwell-Wagner relaxation at intercrystalline contacts.

Influence of the Process for Obtaining Massive Amorphous Materials on the Defects of the Structure in the Alloy Fe61+xCo10-xY8W1B20 , where x = 0 or 1

2018 ◽  
Vol 69 (9) ◽  
pp. 2546-255 ◽  
Author(s):  
Marcin Nabialek ◽  
Bartlomiej Jez ◽  
Kinga Jez
Keyword(s):  
Amorphous Materials ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Amorphous Structure ◽  
Stiffness Parameter ◽  
Copper Mold ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Hysteresis Loops ◽  
Vibration Magnetometer

As part of the work, a rapid cooled alloy was produced with the chemical composition Fe61+xCo10-xY8W1B20, where: x = 0 or 1 using two methods, suction in and injecting the molten alloy into the copper mold. The material was obtained in the form of 10 mm x 5 mm x 0.5 mm plates. Studies on the structure of the obtained alloys were carried out using X-ray diffraction. Obtained X-ray diffraction images are typical for amorphous materials. Using the vibration magnetometer, static magnetic hysteresis loops and primary magnetization curves were measured. The produced samples are characterized by a saturation value above 1T and a coercive field value below 200 A/m. Based on the theory of H. Kronm�ller, numerical analysis of the curves of the original magnetization was carried out. It has been found that the process of magnetizing the produced materials has defects of the amorphous structure in the form of pseudo-location dipoles and free volumes. In addition, the spin wave stiffness parameter was determined.

Structural and Magnetic Properties of the Rapid Cooled Alloys: Fe60Co10Y5+xZr5-xB20 (Where: x = 0 or 2)

2019 ◽  
Vol 70 (1) ◽  
pp. 224-227
Author(s):  
Marcin Nabialek ◽  
Bartlomiej Jez ◽  
Kinga Jez ◽  
Katarzyna Bloch
Keyword(s):  
Room Temperature ◽  
Nanocrystalline Material ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Single Step ◽  
Magnetic Polarization ◽  
X Ray ◽  
High Temperature Alloys ◽  
Magnetic Hysteresis Loops ◽  
Vibration Magnetometer

This article presents the results of tests on high-temperature alloys, produced on the basis of the FeCoB matrix. The nanocrystalline material was produced in a single-step process of rapid cooling of liquid alloy that was injected into a copper mould. Alloy samples were obtained in the form of 10mm x 5mm x 0.5mm tiles. Studies of the structure of the manufactured alloys were undertaken using Bruker X-ray analysis equipment (featuring a CuKa lamp). The magnetic polarization of saturation was measured, as a function of temperature, using a Faraday magnetic balance; the measurements ranged from room temperature up to 850K. Through numerical analysis of the curves, the Curie temperature of the investigated alloys was determined. Using a vibration magnetometer, static magnetic hysteresis loops were measured. The magnetization of saturation of the tested alloys was greater than 1 T, while the coercive field values were 400 and 16600 A/m. The stiffness parameter of the spin wave Dspf was determined.

Preparation and Properties of Zn1-XCoxO Magnetic Microspheres

2010 ◽  
Vol 663-665 ◽  
pp. 1081-1084
Author(s):  
Zhi Fu Liu ◽  
Qing Hong Zhang ◽  
Li Yun Chen ◽  
Yao Gang Li ◽  
Hong Zhi Wang
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Microspheres ◽  
Diffraction Field ◽  
Vibrating Sample Magnetometry ◽  
X Ray ◽  
Transmission Electron ◽  
Magnetic Hysteresis Loops

Zn1-xCoxO magnetic microspheres have been synthesized by a simple solvothermal process. Different Co2+ dopant concentrations have been used as modifier and proved to be efficient at controlling the morphology and magnetic property of Zn1-xCoxO microspheres. The as-synthesized samples are characterized by X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy, photoluminescence spectrophotometer and vibrating sample magnetometry. Magnetic hysteresis loops reveal the samples exhibit ferromagnetic loops at room temperature. The meta-saturation magnetization value and coercivity of Zn0.8Co0.2O reach 0.09 emu·g-1 and 15.0 Oe.

MgB2 Thick Film Grown on Silicon Carbide Substrate by Hybrid Physical-Chemical Vapor Deposition

2007 ◽  
Vol 546-549 ◽  
pp. 2067-2070
Author(s):  
Fen Li ◽  
Tao Guo ◽  
Kai Cheng Zhang ◽  
Li Ping Chen ◽  
Chin Ping Chen ◽  
...  
Keyword(s):  
Magnetic Hysteresis ◽  
Chemical Deposition ◽  
Hysteresis Loops ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bean Model ◽  
Physical Chemical ◽  
Silicon Carbide Substrate ◽  
Magnetic Hysteresis Loops

We have successfully synthesized MgB2 thick films on 4H-SiC substrate by hybrid physical-chemical deposition (HPCVD). They have TC above 40 K, X-ray diffraction (XRD) shows the polycrystal bulk like structure. And JC estimated using magnetic hysteresis loops (MHLs) and Bean model is 7.4 MA/cm2 in self field, at 5 K.

OXIDATION PROCESS OF Fe NANOPARTICLES

2007 ◽  
Vol 21 (18) ◽  
pp. 1143-1151 ◽  
Author(s):  
K. SIMEONIDIS ◽  
S. MOURDIKOUDIS ◽  
I. TSIAOUSSIS ◽  
N. FRANGIS ◽  
M. ANGELAKERIS ◽  
...  
Keyword(s):  
Oxidation Process ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Magnetic Hysteresis Loops ◽  
Conventional Microscopy ◽  
Ft Ir Spectroscopy

The natural oxidation process is studied in the case of 15 nm iron nanoparticles produced by the thermal decomposition of Fe(CO) 5. X-ray diffraction spectra of the nanoparticles at different timescales after exposure to air revealed the instant oxidation of iron and the formation of wüstite and magnetite. Wüstite mainly occupies the interior of nanoparticles, as evidenced by microscopy, but is slowly transformed to a spinel structure. The shape, the dispersion and the role of surfactant were investigated by conventional microscopy and Fourier Transformed-Infrared (FT-IR) spectroscopy. Magnetic hysteresis loops confirmed the expected variation of magnetic properties till the steady state.

Effects of Single-Substitution and Co-Substitution on BiFeO3 Nanoparticles

2014 ◽  
Vol 602-603 ◽  
pp. 23-26
Author(s):  
Xing Ao Li ◽  
Wei Wei Mao ◽  
Xing Fu Wang ◽  
Xi Wang Wang ◽  
Yong Tao Li ◽  
...  
Keyword(s):  
Ferroelectric Properties ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Rhombohedral Structure ◽  
X Ray Diffraction ◽  
Structure Transition ◽  
X Ray ◽  
Multiferroic Bifeo ◽  
Structure Surface ◽  
Magnetic Hysteresis Loops

Multiferroic BiFeO3 nanoparticles have been prepared by solgel method. The effects of single-substituted and co-substituted on the structures and magnetism of all the samples are investigated systematically. X-ray diffraction and Raman spectra results confirm that the samples simulate from a distorted rhombohedral structure to a cubic structure. Surface morphology of the samples were examined by scanning electron microscope (SEM). The ferroelectric and magnetic hysteresis loops shows coexistence of magnetism and ferroelectricity in the room temperature. The structure transition may be the main cause for the origin of improved magnetic and ferroelectric properties.

Mn and MnZn Ferrite Powders Prepared by Detonation of Emulsion Explosives

2011 ◽  
Vol 694 ◽  
pp. 630-634
Author(s):  
Xiao Jie Li ◽  
Xiao Hong Wang ◽  
Hong Hao Yan ◽  
Li Xue ◽  
Ning Luo
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Residual Magnetization ◽  
Average Particle ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Emulsion Explosives ◽  
Mnzn Ferrite ◽  
X Ray ◽  
Transmission Electron

In the present work, nano Mn and MnZn ferrite powders were prepared by detonation of emulsion explosives, XRD(X-ray diffraction),TEM(transmission electron microscope) and VSM(vibrating sample magnetometer) experiments were carried out respectively to characterize and research the prepared powders. Results indicated that the average particle size of the raw Mn and MnZn ferrite powders was around 30nm, and Zn2+ seriously destroyed and reduced the dispersity and homogeneity of the powders although they were successfully doped in nano-Mn ferrite crystals. The average particle size, the specific residual magnetization(σr) and the coercivity(Hc) of the powders were all decreased with the increasing of the hexogen(for short, RDX) content.

Influence of Fe2O3 on Structural and Magnetic Properties of LaFeO3/Fe2O3 and Mn2O3/Fe2O3 Magnetic Nano-Composites

2014 ◽  
Vol 563 ◽  
pp. 30-35 ◽  
Author(s):  
S.F. Wang ◽  
Q.P. Ding ◽  
X.T. Zu
Keyword(s):  
Particle Size ◽  
Sintering Temperature ◽  
Average Particle Size ◽  
Magnetic Nanocomposites ◽  
Average Particle ◽  
Vibrating Sample Magnetometer ◽  
Structural And Magnetic Properties ◽  
Highly Uniform ◽  
Modified Polyacrylamide ◽  
Scanning Electron

LaFeO3/Fe2O3 and Mn2O3/Fe2O3 magnetic nanocomposites have been prepared by a modified polyacrylamide gel route. The XRD result indicates the formation of LaFeO3/Fe2O3 and Mn2O3/Fe2O3 nanocomposites. Scanning electron microscope (SEM) observation shows that the LaFeO3/Fe2O3 particles appear to be regularly spherical in shape and highly uniform in size with a diameter of ~ 80 nm, while the Mn2O3/Fe2O3 sample exhibits a relatively broad particle size distribution with an average particle size centered around 20-60 nm. Result of vibrating sample magnetometer (VSM) of LaFeO3/Fe2O3 magnetic nanocomposites revealed that coercivity values decreased with the increase sintering temperature. However, the coercivity values of Mn2O3/Fe2O3 magnetic nanocomposites appear to an anomaly phenomenon.

scholarly journals Magnetic Properties of FeNi3 Nanoparticle Modified Pinus radiata Wood Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 421 ◽  
Author(s):  
LiLi Wang ◽  
Na Li ◽  
Tiqi Zhao ◽  
Bin Li ◽  
Yali Ji
Keyword(s):  
Photoelectron Spectroscopy ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Wood Composite ◽  
X Ray ◽  
In Situ Fabrication ◽  
Magnetic Hysteresis Loops ◽  
Phase And Chemical Composition ◽  
Modified Wood

Magnetic FeNi3 nanoparticles were synthesized in the internal structure of wood through an in situ fabrication approach. The morphology, crystalline phase and chemical composition of the FeNi3 modified wood was investigated by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). SEM confirmed that the magnetic nanoparticles were densely dispersed in the wood matrix. The magnetic hysteresis loops showed that the magnetism of composites is dependent on the amount of FeNi3 loading. The saturation magnetization of magnetic wood increases from 6.3 to 10.8 emu/g with an increase of FeNi3 loading from 12 to 18 wt %. Furthermore, magnetic wood showed significant directional dependence. The presented work will provide a feasible pathway for producing wood composite products.

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