scholarly journals The controllable magnetic properties of Nico/C nanocomposites

2019 ◽  
Vol 22 (2) ◽  
pp. 92-103
Author(s):  
E. V. Yakushko ◽  
L. V. Kozhitov ◽  
D. G. Muratov ◽  
D. Yu. Karpenkov ◽  
A. V. Popkova
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Phase Analysis ◽  
Carbon Matrix ◽  
Synthesis Temperature ◽  
Linear Increase ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size

The NiCo/C metal-carbon nanocomposites based on the NiCl2/CoCl2/Polyacrylonitrile (PAN) precursors were synthesized using IR heating. The results of studies of NiCo/C nanocomposites by X-ray phase analysis, transmission electron microscopy, and vibration magnetometry showed the dependence of the structure and properties of NiCo/C nanocomposites on the synthesis temperature, concentration, and metal ratio in the precursor. According to the results of the X-ray phase analysis, it was found that during the IR pyrolysis of the precursor, NiCo metal nanoparticles are stabilized in the carbon matrix, an increase in the synthesis temperature from 350 to 800 °C leads to an increase in the average size of nio nanoparticles from 10 to 80 nm, it is established that the formation of the alloy occurs due to the gradual dissolution of cobalt in nickel with the simultaneous transition of cobalt from the hcp modification to FCC. The structure of nanocomposites was shown by transmission electron microscopy of samples synthesized at 600 °C. It was found that with an increase in the metal concentration in the precursor from 10 to 40 wt.%, the average size of NiCo nanoparticles increases and the concentration of nanoparticles in the carbon matrix increases. The study of the magnetic properties of nanocomposites showed that with an increase in the content of metals in the precursor from 10 to 40 wt.%, an almost linear increase in the saturation magnetization from 5.94 to 25.7 A · m2/kg is observed. A change in the ratio of metals from Ni : Co = 4 : 1 to Ni : Co = 1 : 4 causes an increase in magnetization from 11.46 to 23.3 A · m2/kg.

TEM Study of FePt and FePt:C/FePt Composite Double-Layered Thin Films

2013 ◽  
Vol 275-277 ◽  
pp. 1952-1955
Author(s):  
Ling Fang Jin ◽  
Xing Zhong Li
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Magnetic Properties ◽  
Composite Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

New functional nanocomposite FePt:C thin films with FePt underlayers were synthesized by noneptaxial growth. The effect of the FePt layer on the ordering, orientation and magnetic properties of the composite layer has been investigated by adjusting FePt underlayer thickness from 2 nm to 14 nm. Transmission electron microscopy (TEM), together with x-ray diffraction (XRD), has been used to check the growth of the double-layered films and to study the microstructure, including the grain size, shape, orientation and distribution. XRD scans reveal that the orientation of the films was dependent on FePt underlayer thickness. In this paper, the TEM studies of both single-layered nonepitaxially grown FePt and FePt:C composite L10 phase and double-layered deposition FePt:C/FePt are presented.

Synthesis and Magnetic Properties of CoFe2O4 Nano-Particles

2010 ◽  
Vol 148-149 ◽  
pp. 998-1002 ◽  
Author(s):  
Xiao Yun Chen ◽  
Hua Li ◽  
Yue Zeng Su ◽  
Zi Shan Huang ◽  
He Zhou Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Hydrothermal Process ◽  
Nano Particles ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Water Ratio

Spinel CoFe2O4 nano-particles were synthesized by hydrothermal traditionally and Ethylene Glycol (EG) assisted hydrothermal process originally. The effects of reaction temperatures from 140°C to 200°C, different OH- provider and EG/water ratio on the nano-particles’ structure, morphology and magnetic properties of composition were studied by X-ray diffractometer (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The possible mechanism for the effects on the properties was also discussed in details. The results showed that NaAC as OH- provider and higher EG/water ratio in solvent were benefit for getting smaller CoFe2O4 nano-particles. And existence of EG is also important to remove the α-Fe2O3 phase.

Research on Structural Properties of FePt: C Thin Films with FePt Underlayers

2013 ◽  
Vol 385-386 ◽  
pp. 7-10
Author(s):  
Ling Fang Jin ◽  
Hong Zhuang
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Structural Properties ◽  
Composite Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Nonepitaxially grown double-layered films were synthesized with a FePt: C composite layer on top of continuous FePt underlayer. The thickness of FePt was changed from 2 nm to 14 nm. Nanostructures, crystalline orientations and the effect of FePt underlayer on the ordering, orientation and magnetic properties of the thin films were investigated by transmission electron microscopy (TEM) and x-ray diffraction (XRD). XRD confirmed the formation of the ordered L10phase for 5 nm FePt: C film with FePt thickness decreased to 5 nm. TEM studies of FePt:C composite L10phase and double-layered deposition FePt:C/FePt were presented.

Receiving Copper Nanoparticles: Experiment and Modelling

2019 ◽  
Vol 288 ◽  
pp. 140-147 ◽  
Author(s):  
Andrey V. Nomoev ◽  
Erzhena C. Khartaeva ◽  
Natalia V. Yumozhapova ◽  
Tumen G. Darmaev ◽  
S.P. Bardakhanov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Copper Nanoparticles ◽  
Pure Copper ◽  
Current Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Embedded Atom ◽  
Transmission Electron ◽  
Average Size

The copper nanoparticles were obtained by evaporating the metal by the relativistic electron beam. The average size of synthesized particles was about 120 nm. They were characterized by X-ray diffraction, transmission electron microscopy. The results of the X-ray diffraction showed high content of the pure copper for closed setup with an inert gas. Transmission electron microscopy cleared some particles to have an icosahedral structure. These nanoparticles were obtained when the target was exposed by the beam with the highest current strength used in the experiment and the highest cooling of the copper vapor. The process of copper nanoparticle formation by the molecular dynamic method using EAM – potentials (potentials in the Embedded Atom Method form) was studied.

scholarly journals Состав, электронное и атомное строение наночастиц палладия при различных концентрациях металла в матрице полиэтилена

2020 ◽  
Vol 46 (7) ◽  
pp. 20
Author(s):  
С.С. Подсухина ◽  
А.В. Козинкин ◽  
В.Г. Власенко ◽  
Г.Ю. Юрков ◽  
О.В. Попков
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Palladium Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Transmission Electron ◽  
High Pressure Polyethylene ◽  
Average Size ◽  
X Ray Absorption

The composition, electronic and atomic structure of palladium nanoparticles stabilized in high pressure polyethylene (with palladium concentrations of 10 and 20 mass%) were studied by transmission electron microscopy, X-ray diffraction, and X-ray absorption spectroscopy. It was found that nanoparticles consist of metal (Pd) and oxide (Pd2O3) components, and their average size and coordination numbers for first Pd coordination sphere decrease(from 7 to 6 nm and from 7 to 5.7, respectively) with a decrease in metal concentration.

Preparation and characteristics of 90° rotated biepitaxial Fe3O4 thin films

2002 ◽  
Vol 17 (8) ◽  
pp. 1985-1991 ◽  
Author(s):  
Hiroshi Matsuda ◽  
Hiroshi Sakakima ◽  
Hideaki Adachi ◽  
Akihiro Odagawa ◽  
Kentaro Setsune
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Electron Diffraction ◽  
Grain Boundary ◽  
Seed Layer ◽  
Tunneling Magnetoresistance ◽  
X Ray ◽  
Transmission Electron

In-plane 90° rotated biepitaxial Fe3O4 thin films have been successfully prepared onto MgO (110) substrates using a CeO2 seed layer and their microstructure, electric, and magnetic properties were investigated. From the x-ray φ-scan measurements, the in-plane epitaxial relations were determined as 〈110〉Fe3O4//〈110〉MgO and 〈001〉Fe3O4//〈001〉MgO for the no-seeded Fe3O4 layer, and 〈001〉Fe3O4//〈110〉MgO and 〈110〉Fe3O4//〈001〉MgO for the CeO2 (110) seeded Fe3O4 layer. The CeO2 seed layer was found to rotate the upper Fe3O4 lattice at 90° upon normal axis to the layer against the no-seeded Fe3O4. The transmission electron microscopy and electron diffraction analyses revealed that the transition region of the biepitaxial Fe3O4 boundary between CeO2-seeded and no-seeded portions consisted of columnarlike polycrystalline grains. The Fe 3O4 films exhibited single-crystallinelike electric and magnetic properties, however, substantial spin-dependent-tunneling magnetoresistance across the 90° grain boundary was not observed even in the antiparallel situation for each Fe3O4 portion.

scholarly journals Electrospinning Synthesis of Fe3O4/Eu(DBM)3phen/PVP Multifunctional Microfibers and Their Structure, Luminescent and Magnetic properties

2021 ◽  
Author(s):  
Ruifei Qin ◽  
lina liu
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Electrospinning Process ◽  
Europium Complex ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Characteristic Emission ◽  
Average Size

Abstract Multifunctional Fe3O4/Eu(DBM)3phen/PVP ((DBM: dibenzoylmethane, phen: 1,10-phenanthroline, PVP: polyvinyl pyrrolidone) microfibers were constructed by simple electrospinning process. The structure and morphology of the microfibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The diameters of pure PVP microfibers and the microfibers doped only with Fe3O4 nanoparticles (NPs) were uniformly distributed, with an average size of about 360 nm. When 3% Eu(DBM)3phen complex and Fe3O4 NPs were both added to the precursor for electrospinning, the microfibers became very inhomogeneous in diameter. The photoluminescent properties of pure Eu(DBM)3phen complex and composite microfibers were also studied. The characteristic emission peaks of Eu3+ appeared in the composite microfibers. The intensities of emission and excitation spectra gradually decrease with adding more Fe3O4 NPs. The unit mass of the pure europium complex in some composite microfibers gave stronger luminescence than the pure europium complex. The fluorescence lifetime of 5D0 state in the composite microfibers is longer than that of pure europium complex. Additionally, the magnetic properties of Fe3O4 NPs and the composite microfibers were investigated. Fe3O4 NPs and composite microfibers were both superparamagnetic. The saturation magnetization of the composite microfibers was smaller than that of pure Fe3O4 NPs.

Pure and Ca-doped LaCoO3 Nanopowders: Sol-Gel Synthesis, Characterization and Magnetic Properties

2004 ◽  
Vol 848 ◽  
Author(s):  
Lidia Armelao ◽  
Davide Barreca ◽  
Gregorio Bottaro ◽  
Andrea Caneschi ◽  
Claudio Sangregorio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Chemical Composition ◽  
Auger Electron ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Synthesis

ABSTRACTThis work is focused on the sol-gel synthesis of pure and Ca-doped LaCoO3 nanopowders. The samples were prepared starting from methanolic solutions of cobalt (II) acetate (Co(CH3COO)2·4H2O), lanthanum (III) nitrate (La(NO3)3·6H2O) and calcium (II) acetate (Ca(CH3COO)2·H2O). After solvent evaporation, the obtained powders were dried under vacuum and subsequently treated in air up to 1273 K. The system evolution under thermal annealing was studied by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), while the chemical composition was analyzed by X-ray Photoelectron (XPS) and X-ray Excited Auger electron (XE-AES) spectroscopies. The temperature and field dependence of the magnetic properties of the Ca-doped samples were investigated, and compared to those of the corresponding pure LaCoO3 powders.

Effect performance of the nanomagnetic properties of Ni–Cu–Co ferrites by Al3+ ions adulteration

2020 ◽  
Vol 34 (05) ◽  
pp. 2050059 ◽  
Author(s):  
Nanzhaxi Suo ◽  
Aimin Sun ◽  
Lichao Yu ◽  
Zhuo Zuo ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Fourier Transform ◽  
Crystallite Size ◽  
Spinel Structure ◽  
Average Crystallite Size ◽  
Doping Amount ◽  
X Ray ◽  
Transmission Electron

In this paper, aluminum-doped Ni–Cu–Co ferrite nanomagnetic material powder was prepared by sol–gel technique using citric acid as a complexing agent and high-purity nitrate as raw material. The effect of doping amount of different Al[Formula: see text] ions on the structure and magnetic properties of ferrites has been studied. The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Energy dispersive X-ray (EDX) and Vibrating sample magnetometer (VSM) were used to characterize the structural and magnetic properties of ferrite. The XRD analysis showed that all samples of Ni–Cu–Co ferrites have a single-phase cubic spinel structure. Average crystallite size was calculated by the Debye–Scherrer formula and it was found that the average crystallite size of the sample was affected by the doping concentration. As the amount of Al[Formula: see text] ion doping increases, the crystallite size decreases from 54.88 nm to 46.09 nm. The absorption peak of Fourier transform infrared spectroscopy (FTIR) at 590 cm[Formula: see text] further indicates the formation of cubic spinel structure of Ni–Cu–Co ferrite. Transmission electron microscopy (TEM) images show the presence of particles which are spherically cubic-shaped particles. The constituent elements of the samples were analyzed by EDX spectroscopy. In addition, the ferromagnetism of the samples was confirmed by VSM measurements. The saturation magnetization (Ms) and remanent magnetization (Mr) first increase and then decrease when the aluminum ion concentration increases. Compared with pure samples and other doped samples, they have the best magnetic properties when the doping amount of Al[Formula: see text] ions is [Formula: see text]. It also shows that the prepared samples are suitable for magnetic recording materials.

Preparation, Characterization and Magnetic Property of MFe2O4 (m=Mn, Zn, Ni, Co) Nanoparticles

2013 ◽  
Vol 842 ◽  
pp. 35-38 ◽  
Author(s):  
Li Xia Yang ◽  
Sha Li ◽  
Jing Zhang ◽  
Zhou Chen ◽  
Shi Cheng Xu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Basic Source ◽  
Co Nanoparticles ◽  
Zn Nanoparticles

MFe2O4 (M=Mn, Co, Ni, Zn) Nanoparticles with diameters from 5nm to 30nm have been prepared through a hydrothermal method. In this system, ethanolamine was used as a basic source instead of NaOH. The as-prepared ferrites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In addition, the magnetic properties of the obtained ferrites have been studied at room temperature, showing that the magentic properties of ferrites closely depended on the chemical composition of M2+.

Sign in / Sign up

Export Citation Format

Share Document