Microstructure and Magnetic Properties of Fe(C) and Fe(O) Nanoparticles

2001 ◽  
Vol 704 ◽  
Author(s):  
Xiang-Cheng Sun ◽  
N. Nava ◽  
J. Reyes-Gasga
Keyword(s):  
Room Temperature ◽  
Arc Discharge ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hrtem Observation ◽  
Average Grain Size ◽  
Fe Nanoparticles ◽  
Carbon Coated

AbstractTwo types of iron (Fe) nanoparticles, carbon-coated Fe nanoparticles (Fe(C)) and pure α-Fe nanoparticles that coated with oxide layers (Fe(O)), have been successfully synthesized using modified graphite arc-discharge method. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HREM) and electron diffraction (SAED) analysis have been used to characterize these distinct structural morphologies. It is indicated that those two Fe nanoparticles have an average grain size of 15-20nm. The presence of carbon encapsulated α-Fe, γ-Fe and Fe3C phases are clearly identified by X-ray diffraction and SAED patterns in those Fe(C) particles. However, the evidence of pure α-Fe nanocrystal coated with oxide layer is also revealed by HR-TEM images and SAED patterns in these Fe(O) particles.Mössbauer spectra and hyperfine magnetic fields at room temperature for the assemblies of Fe(C) and Fe(O) nanoparticles further confirm their distinct nanophases that detected by XRD analysis and HRTEM observation. Specially, the assemblies of Fe(O) nanoparticles exhibit ferromagnetic properties at room temperature due to the stronger interparticle interaction and bigger magnetocrystalline anisotropy effects among these Fe(O) nanoparticles. Moreover, modified superparamagnetic relaxation is observed in the assemblies of Fe(C) nanoparticles, which is attributed to the nanocrystalline nature of the carbon-coated nanoparticles.

scholarly journals Photo-acoustic properties of nanoTiO2:Er

2016 ◽  
Vol 5 (4) ◽  
pp. 196
Author(s):  
R. Palomino-Merino ◽  
R. Lozada-Morales ◽  
J. Martínez-Juárez ◽  
G. Juárez-Díaz ◽  
J. Carmona-Rodriguez ◽  
...  
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Acoustic Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Electron Dispersion ◽  
Er Doped ◽  
Spectroscopy Optical

Nanocrystalline Er-doped TiO2 was prepared by sol-gel at room temperature. X-ray diffraction, photoacoustic spectroscopy (optical absorption), transmission electron microscopy (TEM), and electron dispersion microscopy (EDS) were carried out on both as-prepared and thermally-annealed (air at 700 ºC) samples, revealing the anatase crystalline phase of TiO2. The samples exhibit an average grain size from 38 to 5.1 nm, as the nominal concentration of Er varies from 0 % to 7 %. The photoacoustic spectra evidence the absorption edge at 300 nm attributed to TiO2, as well as several electronic transitions which are atomic energy absorption-line levels characteristics of Er.

scholarly journals Effect of Nd Substitution on the Microstructural and Dielectric Properties of Polycrystalline Ca(Ti0.5Fe0.5)O3

2013 ◽  
Vol 61 (1) ◽  
pp. 125-129 ◽  
Author(s):  
MR Shah ◽  
MR Amin ◽  
AKM Akther Hossain
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Average Grain Size ◽  
Iron Titanate ◽  
Higher Temperature ◽  
Calcium Iron

Neodymium substituted calcium iron titanate having the general formula Ca1-xNdx(Ti0.5Fe0.5)O3 were prepared by the standard solid state reaction technique at relatively higher temperature (1473 K). X-ray diffraction (XRD) and optical microscopy are used to carry out the structural analysis and surface morphology, respectively. The XRD analysis confirms that all compositions are single phase orthorhombic in structure. The lattice parameters and the average grain size are found to decrease but the density to increase with the increase in Nd content. The dielectric constant (?/), dielectric loss (tan?) and ac conductivity (?ac) are studied at room temperature as a function of frequency and compositions. The room temperature ?/ is found to decrease with the increase in frequency and Nd content. On the other hand, the tan? and ?ac are observed to increase with the increase in frequency and decrease with the increase in Nd content. Dhaka Univ. J. Sci. 61(1): 125-129, 2013 (January) DOI: http://dx.doi.org/10.3329/dujs.v61i1.15113

scholarly journals Carbon-coated magnetic particles increase tissue temperatures after laser irradiation

2015 ◽  
Vol 08 (05) ◽  
pp. 1550018 ◽  
Author(s):  
Shupeng Liu ◽  
Na Chen ◽  
Fufei Pang ◽  
Zhengyi Chen ◽  
Tingyun Wang
Keyword(s):  
Laser Irradiation ◽  
Magnetic Particles ◽  
Laser Energy ◽  
Thermal Therapy ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fbg Sensor ◽  
Transmission Electron ◽  
Carbon Coated

Purpose: This work focused on the investigation the hyperthermia performance of the carbon-coated magnetic particles (CCMPs) in laser-induced hyperthermia. Materials and methods: We prepared CCMPs using the organic carbonization method, and then characterized them with transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). In order to evaluate their performance in hyperthermia, the CCMPs were tested in laser-induced thermal therapy (LITT) experiments, in which we employed a fully distributed fiber Bragg grating (FBG) sensor to profile the tissue's dynamic temperature change under laser irradiation in real time. Results: The sizes of prepared CCMPs were about several micrometers, and the LITT results show that the tissue injected with the CCMPs absorbed more laser energy, and its temperature increased faster than the contrast tissue without CCMPs. Conclusions: The CCMPs may be of great help in hyperthermia applications.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

scholarly journals Facile Organometallic Synthesis of Fe-Based Nanomaterials by Hot Injection Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1141
Author(s):  
Georgia Basina ◽  
Hafsa Khurshid ◽  
Nikolaos Tzitzios ◽  
George Hadjipanayis ◽  
Vasileios Tzitzios
Keyword(s):  
Room Temperature ◽  
Colloidal Particles ◽  
Iron Pentacarbonyl ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Organometallic Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Hot Injection ◽  
The Stability

Fe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer. The injection temperature plays a very crucial role and higher temperatures enhance the stability and the resistance against oxidation. For the case of injection at 315 °C, the nanoparticles had around a 10 nm mean diameter and revealed 132 emu/g. Remarkably, a stable dispersion was created due to the colloids’ surface functionalization in a nonpolar solvent.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

Preparation and Properties of Nano-Crystalline Cellulose Electro-Rheological Fluid

2015 ◽  
Vol 815 ◽  
pp. 217-221
Author(s):  
Ling Li Xu ◽  
Xing Ling Shi ◽  
Qing Liang Wang
Keyword(s):  
Room Temperature ◽  
Silicone Oil ◽  
Strong Acid ◽  
Crystalline Cellulose ◽  
Methyl Silicone ◽  
Shearing Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron

nanocrystalline cellulose (NCC) was prepared from micro-crystalline cellulose (MCC) by strong acid hydrolysis. The characteristics of such particle were studied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Electro-rheological fluids (ERF) were prepared by dispersing NCC and MCC in methyl-silicone oil, and their ER effects were measured. Experimental results indicated that NCC ERF exhibited a remarkable ER effect. The highest static shearing stress of NCC ERF (3.5 g/ml) was 5.1 kPa at the room temperature under a 4 .2 kV/mm electric field, increased about 5.5 times compared to MCC ERF, and sedimentation of NCC ERF was not observed even after 60 days.

scholarly journals Effect of Re and Tm-site on morphology structure and optical band gap of ReTmO3 (Re: La, Ce, Nd, Gd, Dy, Y and Tm: Fe, Cr) prepared by sol-gel method

2018 ◽  
Vol 64 (4) ◽  
pp. 381
Author(s):  
Muhammad Tufiq Jamil ◽  
Javed Ahmad ◽  
Syed Hamad Bukhari ◽  
Murtaza Saleem
Keyword(s):  
Band Gap ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Average Grain Size ◽  
Auto Combustion ◽  
Uv Visible

Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReT mO3 (Re = La, Nd, Gd, Dy, Y and T m = Fe, Cr) have been synthesized by sol-gel auto combustion citrate method. The samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy. The samples are single phase as confirmed by XRD analysis and correspond to the orthorhombic crystal symmetry with space group pbnm. Debye Scherer formula and Williamson Hall analysis have been used to calculate the average grain size which is consistent with that of determined from SEM analysis and varied between 25-75 nm. The elemental compositions of all samples have been checked by EDX analysis. Different crystallographic parameters are calculated with strong structural correlation among Re and Tm sites. The optical energy band gap has been calculated by using Tauc relation estimated to be in the range of 1.77 - 1.87 eV and 2.77 - 3.14 eV, for ReFeO3 and ReCrO3, respectively.

New method for the production of bulk amorphous materials of Nd–Fe–B alloys

2005 ◽  
Vol 20 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Tetsuji Saito ◽  
Hiroyuku Takeishi ◽  
Noboru Nakayama
Keyword(s):  
Electron Microscopy ◽  
Amorphous Materials ◽  
Room Temperature ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons

We report a new compression shearing method for the production of bulk amorphous materials. In this study, amorphous Nd–Fe–B melt-spun ribbons were successfully consolidated into bulk form at room temperature by the compression shearing method. X-ray diffraction and transmission electron microscopy studies revealed that the amorphous structure was well maintained in the bulk materials. The resultant bulk materials exhibited the same magnetic properties as the original amorphous Nd–Fe–B materials.

Characterization of Fe–Ni(C) nanocapsules synthesized by arc discharge in methane

1999 ◽  
Vol 14 (5) ◽  
pp. 1782-1790 ◽  
Author(s):  
X. L. Dong ◽  
Z. D. Zhang ◽  
S. R. Jin ◽  
W. M. Sun ◽  
X. G. Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Arc Discharge ◽  
Carbon Layer ◽  
Magnetization Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Energy Disperse Spectroscopy

Ultrafine Fe–Ni(C) particles of various compositions were prepared by arc discharge synthesis in a methane atmosphere. The particles were characterized by x-ray diffraction, transmission electron microscopy, energy disperse spectroscopy, chemical analysis, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and magnetization measurement. The carbon atoms solubilizing at interstitial sites in γ–(Fe, Ni, C) solution particles have the effects of forming austenite structure and changing microstructures as well as magnetic properties. A carbon layer covers the surface of Fe–Ni(C) particles to form the nanocapsules and protect them from oxidization. The mechanism of forming Fe–Ni(C) nanocapsules in the methane atmosphere was analyzed.

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