scholarly journals Morphological and magnetic features of columnar nanostructures CuO

2021 ◽  
Vol 2094 (2) ◽  
pp. 022002
Author(s):  
A V Ushakov ◽  
I V Karpov ◽  
L Yu Fedorov ◽  
V G Demin
Keyword(s):  
Magnetic Measurements ◽  
Magnetic Hysteresis ◽  
Coherent Scattering ◽  
Magnetic Hysteresis Loop ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Monoclinic Crystal Structure ◽  
Ionic Nature

Abstract Columnar nanostructures (CNS) were grown by plasma chemical synthesis at a gas mixture pressure of 90% He + 10% O2 200 Pa and substrate temperatures of 340K (sample 1) and 370K (sample 2). The effect of substrate temperature on the morphological, crystalline, magnetic, and impedance properties of CNS was studied. Scanning microscopy (SEM) showed that the morphology of CNS varies significantly from dendritic to wire structure. Energy dispersive X-ray spectroscopy (EDS) showed a change in the stoichiometry of the deficiency samples (Cu52O48) to an excess of oxygen (Cu42O58). X-ray diffraction analysis (XRD) and Rietveld fitting showed that samples 1 and 2 have a monoclinic crystal structure with a large proportion of the amorphous phase, the size of coherent scattering regions (CSR) was 26 nm (sample 1). Magnetic measurements showed that sample 1 exhibits ferromagnetic behavior, and at 6 K a magnetic hysteresis loop appears. Sample 2 from 250 K to room temperature exhibits diamagnetic behavior. A connection was found between the appearance of diamagnetism and a jump in the dielectric constant of sample 2. An assumption was made about the electron-ionic nature of the diamagnetism of sample 2.

scholarly journals Structural, Magnetic and Optical Properties of Gd and Co Co-Doped YFeO3 Nanopowders

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2423 ◽  
Author(s):  
Meng Wang ◽  
Ting Wang
Keyword(s):  
Optical Properties ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Optical Fields ◽  
Solid State Reaction Technique ◽  
Co Doping ◽  
Distorted Structure ◽  
Co Doped

YFeO3, YFe0.95Co0.05O3, Y0.95Gd0.05FeO3 and Y1−xGdxFe0.95Co0.05O3 (x = 0.0, 0.05, 0.10, 0.15 and 0.20) nanopowders were successfully fabricated via a low-temperature solid-state reaction technique. Results obtained using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectra indicate that YFeO3 nanopowders with Gd3+ and Co3+ ions co-doping at Y and Fe-sites were fabricated at 800 °C in sizes below 50 nm, and a distorted structure was obtained. Magnetic hysteresis loop analyses illustrate that ferromagnetic behavior of YFeO3 nanopowders can be enhanced with the addition of Gd and Co. Whereas the maximum and remnant magnetization of the powders were found to be about 5.24 and 2.6 emu/g, respectively, the optical band gap was around 2.4 eV, proving that co-doped YFeO3 nanopowders have a strong capability to absorb visible light. Because both magnetic and optical properties of these materials are greatly improved with the addition of Gd and Co, one can expect the scope of their potential application in the magnetic and optical fields to increase.

Magnetic Properties of Manganese-Titanium Substituted Barium Ferrite Ba(TiMn)xFe12-2xO19(x=0.0, 0.5, 1.0, 1.5, 2.0) Prepared by the Molten Salt Method

2010 ◽  
Vol 434-435 ◽  
pp. 240-243 ◽  
Author(s):  
Hai Feng Li ◽  
Rong Zhou Gong ◽  
Hao Luo ◽  
Jun Zhou ◽  
Li Ren Fan ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Molten Salt ◽  
Barium Ferrite ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Electromagnetic Properties ◽  
Molten Salt Method ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray

M-type hexaferrites Ba(TiMn)xFe12-2xO19 (x=0 to 2) powders were synthesized by molten salt method. X-ray diffraction, scanning electron microscope and vibrating sample magnetometer were used to analyze the structures and electromagnetic properties. The results showed that, the magnetoplumbite structures for all samples were formed. Magnetic hysteresis loop measurements of the Ba(TiMn)xFe12-2xO19, exhibitted that the saturation magnetization (Ms), the remanent magnetization (Mr) and the coercitivity (Hc) of compounds depended strongly on the chemical composition of materials. The maxium values of Ms (52.68emu/g) and Mr (32.89emu/g) of the compounds were found at x=0.5; however, the values of Hc and the areas of magnetic hysteresis loop of compounds decreased with increasing the value of x. The Ba(TiMn)1.5Fe9O19/paraffin wax composites containing 40vol% of doped barium ferrite exhibitted good absorption performances in the frequency range of 2–14 GHz.

scholarly journals Reducing the ordering temperature of FePt nanoparticles by Cu additive and alternate reduction method

2017 ◽  
Vol 07 (06) ◽  
pp. 1750039
Author(s):  
Fang Wang ◽  
Xiaojun Bai
Keyword(s):  
Annealing Temperature ◽  
Reduction Method ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Metal Salts ◽  
Fept Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Cu Additive

(FePt)[Formula: see text]Cu[Formula: see text] nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium. Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature. Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature. It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.

Influence of Zinc-Zirconium Substitution on Magnetic Properties of Ba(ZnZr)xFe12-2xO19 Hexaferrite Prepared by the Molten Salt Method

2009 ◽  
Vol 79-82 ◽  
pp. 2071-2074 ◽  
Author(s):  
Hai Feng Li ◽  
Rong Zhou Gong ◽  
Xian Wang ◽  
Li Ren Fan ◽  
Gang He ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Molten Salt ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Chemical Compositions ◽  
Molten Salt Method ◽  
Vibrating Sample Magnetometer ◽  
Hexagonal Ferrites ◽  
X Ray Diffraction ◽  
X Ray

M-type hexaferrites Ba(ZnZr)xFe12-2xO19 (x=0, 0.5, 1.0, 1.5) powders, have been synthesized by molten salt method, where x varies from 0 to 1.5 in steps of 0.5. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer(VSM) were used to analyze the structures and magnetic properties. The results showed that, the magnetoplumbite structures for all samples calcining at 1100°C have been formed. The magnetic hysteresis loop measurements of the hexagonal ferrites powders showed that the saturation magnetization (Ms), the remanent magnetization (Mr), and the coercitivity (Hc) of ferrites depend strongly on the chemical compositions of materials. The data showed that the max Hc was obtained when substitution of x=1.0 (Hc=63.9 Oe), while the best Ms was obtained when substitution of x=0.5 (Ms=54.02 emu/g). Zn and Zr substitutions greatly modified the magnetic properties of BaM hexaferrite.

scholarly journals Doped Nanostructured Manganese Ferrites: Synthesis, Characterization, and Magnetic Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Sami-ullah Rather ◽  
Usman Saeed ◽  
Abdulrahim Ahmad Al-Zahrani ◽  
Hisham S. Bamufleh ◽  
Hesham Abdulhamed Alhumade ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Tetrahedral Site ◽  
Magnetic Hysteresis ◽  
Treatment Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Ionic Nature ◽  
Nanocrystalline Aluminum ◽  
Iron And Manganese

Nanocrystalline aluminum-doped manganese ferrite was synthesized by facile thermal treatment method. Nanostructure-doped ferrite with crystalline size that ranged between 3.71 and 6.35 nm was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and vibrating-sample magnetometry (VSM). The Scherrer and Williamson-Hall hypothesis techniques were utilized to determine lattice constants and strain. Various types of structural properties including octahedral and tetrahedral site radius, bond lengths and angles, hopping parameter, oxygen positional parameters, site bonds, and edge lengths were determined from XRD spectrum analysis. Discrepancy in the hypothetically expected angle indicates improvement of A-B superexchange intercommunication. Furthermore, magnetic-hysteresis (M-H) and XPS analysis support the claim of enhancement. The presence of the ionic nature of iron and manganese in ferrite is FeII, FeIII, MnII, and MnIV as revealed by the results of XPS. Moreover, XPS assists in an excellent way to understand the properties such as configuration, chemical nature, and average inversion degree of doped ferrite samples. The spin noncollinearity and exquisite interaction amid the sublattice are responsible for the decrease in the saturation and remnant magnetization determined from the hysteresis loop at ambient temperature with maximum magnetic field of 1.8 T.

scholarly journals A new crystalline form of αβ-D-lactose prepared by oven drying a concentrated aqueous solution of D-lactose

2019 ◽  
Vol 75 (7) ◽  
pp. 904-909 ◽  
Author(s):  
Daniel Nicholls ◽  
Carole Elleman ◽  
Norman Shankland ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Three Dimensional ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Monoclinic Crystal Structure ◽  
High Degree ◽  
Triclinic Form

A new crystalline form of αβ-D-lactose (C12H22O11) has been prepared by the rapid drying of an approximately 40% w/v syrup of D-lactose. Initially identified from its novel powder X-ray diffraction pattern, the monoclinic crystal structure was solved from a microcrystal recovered from the generally polycrystalline mixed-phase residue obtained at the end of the drying step. This is the second crystalline form of αβ-D-lactose to be identified and it has a high degree of structural three-dimensional similarity to the previously identified triclinic form.

Superparamagnetic Behavior of Granular Co-C Films Consisting of Nanocrystalline Cobalt Encapsulated in Carbon

2000 ◽  
Vol 614 ◽  
Author(s):  
Hao Wang ◽  
S.P. Wong ◽  
W.Y. Cheung ◽  
N. Ke ◽  
M.F. Chiah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Magnetic Measurements ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Vacuum Arc ◽  
Zero Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy

ABSTRACTNanocomposite Co-C thin films of about 15 nm thick were prepared by pulsed filtered vacuum arc deposition. The films were characterized by x-ray photoelectron spectroscopy, non-Rutherford backscattering spectrometry, x-ray diffraction, magnetic force microscopy and magnetic measurements. The as-deposited films were amorphous. After annealing at 350°C for one hour in vacuum (< 10−3 Pa), the films were found to consist of nanocrystalline Co grains encapsulated in carbon. The superparamagnetism of the annealed Co36C64 film was demonstrated by the measurement of DC susceptibility and magnetic hysteresis using a SQUID magnetometer. The superparamagnetic relaxation blocking temperature was marked to be about 12K by the peak of the zero-field-cooled magnetization under a field of 100 Oe. The magnetic properties of these annealed granular Co-C films transform from superparamagnetism to ferromagnetism when the Co concentration increases.

STRUCTURE AND MAGNETIC PROPERTIES OF Co-DOPED SnO2 NANOWIRES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 967-971 ◽  
Author(s):  
U. K. GOUTAM ◽  
SHASHWATI SEN ◽  
JAGANNATH ◽  
A. K. SINGH ◽  
R. MUKUND ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
Tubular Furnace ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Sno2 Nanowires ◽  
Tin Metal ◽  
Co Doped

Co -doped SnO2 nanowires were grown by thermal evaporation of a mixture of Tin metal powder and CoCl2 · 6H2O in a tubular furnace. The growth occurs by vapor–solid growth mechanism. Nanowires grew along the sidewall of the alumina boat placed in the tubular furnace and the diameter of these nanowires (as was evident from scanning electron microscopy), was found to be in the range of 50 nm to 200 nm. Co was successfully doped in SnO2 lattice as revealed by X-ray diffraction data and was found to be in Co2+ state in the nanowires as detected by X-ray Photoelectron Spectroscopy measurements. Room temperature magnetic measurements, carried out using Vibrating Sample Magnetometer, indicated ferromagnetic behavior of the nanowires indicating their potential for spintronics applications. With increasing Co doping (upto 1%), the lattice parameters of SnO2 decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship.

Structural and magnetic properties of pure and cobalt doped Gallium Nitride nanocrystals

2010 ◽  
Vol 1257 ◽  
Author(s):  
Vottikondala Ganesh ◽  
Suresh Sundaram ◽  
Krishnan Baskar
Keyword(s):  
Magnetic Properties ◽  
Gallium Nitride ◽  
Magnetic Measurements ◽  
Raw Materials ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
Co Doped

AbstractIn the present study pure and doped gallium nitride (GaN) nanocrystals were synthesized using gallium trichloride (GaCl3), ethylene diamine tetra acetic acid (EDTA) and cobalt chloride as raw materials at a temperature of 900 °C in ammonia (NH3) atmosphere. The XRD spectrum for pure and cobalt doped GaN nanocrystals shows the formation of single phase wurtzite structure. No impurity phases were observed in the X-ray diffraction pattern for 5% Co doped sample whereas secondary phases were observed when the doping concentration exceeds 5 %. Shift in X-ray diffraction peaks were observed in Co doped samples towards lower angle side compared to pure GaN, it confirms that the Co atoms introduces in to the GaN lattice. Transmission electron microscopy images were taken for pure and Co doped GaN. Hexagonal morphology was observed in pure GaN samples. The average size of the particle was found to be ˜20 nm for pure and Co doped GaN. The magnetic measurements were carried out for the Co (5% & 10%) doped samples both at 10K and 300K. Clear hysteresis loop in the magnetization curve suggest the presence of ferromagnetic behavior in cobalt doped GaN. Temperature dependent magnetization (M-T) measurements were also carried out for doped samples using Super Conducting Quantum Interface Device (SQUID) from 10K to 300K The results have been discussed and correlated to structural and magnetic properties of the materials.

Preparation of Coral-Like α-Fe2O3 Nanostructures and Magnetic Properties

2011 ◽  
Vol 194-196 ◽  
pp. 625-628
Author(s):  
Hong Wang ◽  
Min Gong ◽  
Jing Yu Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Ferromagnetic Behavior ◽  
Average Thickness ◽  
Solvothermal Process ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Coral-like α-Fe2O3nanostructures modified by surfactant CTAB have been successfully obtained via a solvothermal process by using FeCl36H2O and oxalic acid as the starting materials. The coral-like α-Fe2O3nanostructures with good-crystalline consist of well-aligned α-Fe2O3nanoflakes with an average thickness of about 40 nm growing radially from the center of the nanostructures. The obtained products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), superconducting quantum interference device magnetometer (SQUID). Magnetic hysteresis measurements indicate that coral-like α-Fe2O3superstructures show a normal ferromagnetic behavior with the remanence and coercivity of 0.2346emu/g and 1862Oe at room temperature. CTAB, the reaction temperature and solvent played an important role in controlling the final morphology of the products.

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