PREPARATION, STRUCTURAL CHARACTERIZATION AND MAGNETIC PROPERTIES OF La-SUBSTITUTED Co FERRITES VIA A MODIFIED CITRATE PRECURSOR ROUTE

2009 ◽  
Vol 23 (27) ◽  
pp. 3289-3297 ◽  
Author(s):  
LUNHONG AI ◽  
JING JIANG
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Fourier Transform ◽  
Thermal Evolution ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Ftir Spectrometer ◽  
Precursor Route ◽  
Citrate Precursor

CoLa x Fe 2-x O 4 (x = 0.00, 0.05 and 0.1) nanoparticles were prepared simply by a modified citrate precursor route. Effects of La -substituting level on the their magnetic properties were investigated on the basis of the structural analysis. The thermal evolution of the precursor, as well as the microstructure of as-prepared products were studied by means of a thermogravimetric analyzer (TGA), X-ray diffractometer (XRD) and Fourier transform infrared (FTIR) spectrometer. The magnetic properties of the as-prepared samples were measured using a vibrating sample magnetometer (VSM). It was found that the magnetic properties were dependent on many factors such as La -substituting level, particle size and microstructure. The observed saturation magnetization decreased with increasing La content, whereas coercivity exhibited reverse behavior.

ZnFe2O4 Modified by Fe(NO3)3 for the Synthesis of Ionic Ferrofluids

2010 ◽  
Vol 177 ◽  
pp. 32-36 ◽  
Author(s):  
An Rong Wang ◽  
Jian Li ◽  
Qing Mei Zhang ◽  
Hua Miao
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Znfe2o4 Nanoparticles

Weak magnetic ZnFe2O4 nanoparticles were prepared by coprecipitation and treated with different concentrations of Fe(NO3)3 solution. Untreated and treated particles were studied using a vibrating sample magnetometer, transmission electron microscope, by X-ray diffraction, X-ray energy dispersive spectroscopy and X photoelectron spectroscopy. The results showed that, after treatment, the ZnFe2O4/γ-Fe2O3 forms disphase nanoparticles, with enlarged size, enhanced magnetic properties and with a surface parceled with Fe(NO3)3. The size of the particles and their magnetic properties are related to the concentration of the treatment solution. The particle size and magnetic properties could be controlled by controlling the concentration of treating solution, therefore nanoparticles can be more widely used.

STRUCTURAL PROPERTIES OF NANOCRYSTALLINE Ni–Al SPINEL FERRITES

2011 ◽  
Vol 25 (08) ◽  
pp. 1121-1125 ◽  
Author(s):  
A. T. RAGHAVENDER
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Structural Properties ◽  
Lattice Constant ◽  
Reaction Mechanisms ◽  
Sol Gel ◽  
Ftir Analysis ◽  
X Ray ◽  
Al Content ◽  
Ftir Spectrometer

Ultra fine NiAl x Fe 2-x O 4(0 ≤ x ≤ 1) nanopowders were synthesized by sol-gel method and their structural properties were investigated using X-ray diffractometer (XRD) and fourier transform infrared (FTIR) spectrometer. The particle size D, lattice constant a, density dx decreased with increasing non-magnetic Al content x. The combustion reaction mechanisms were explained with the help of FTIR analysis.

Comparison of the Crystalline Structure and Magnetic Properties in Coprecipitated CoFe2O4 and CoLa0.1Fe1.9O4

2020 ◽  
Vol 855 ◽  
pp. 16-21
Author(s):  
Riyana Indah Setiyani ◽  
Utari ◽  
Yofentina Iriani ◽  
Budi Purnama
Keyword(s):  
Magnetic Properties ◽  
Fourier Transform ◽  
Crystalline Structure ◽  
Atomic Radius ◽  
Nano Particles ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Bonding Structure ◽  
Previous Discussion ◽  
Lanthanum Cation

Comparison of the crystalline structure and magnetic properties in CoFe2O4 and CoLa0.1Fe1.9O4 nanoparticles have been studied. The obtained samples are characterized by using X-Ray Diffractometer (XRD), Fourier Transform InfraRed (FTIR) and Vibrating Sample Magnetometer (VSM). The XRD results show that the crystallite size of the samples are 24.539 nm and 28.772 nm for the CoFe2O4 and CoLa0.1Fe1.9O4 nano particles, respectively. Furthermore, the crystalline strain is 0.00460 and lightly decreases to 0.00392 with the presence of lanthanum. The different of the atomic radius for both Fe3+ (1.26 Å) and La3+ (1.87 Å) should attribute to the change of the crystalline strain. FTIR results show that the absorption peak of the CoFe2O4 occur at k = 591.21/cm and the CoLa0.1Fe1.9O4 is 594.10/cm. This indicate that the lanthanum cation successfully substitutes to the original bonding-structure of the CoFe2O4. VSM results show that the HC are 1.02 kOe and 0.705 kOe for the samples without and with La3+ cations. Moreover, the MS is equal 69.625 emu/g and decrease of 55.70 emu/g with the present of the La3+ cations. Finally, the strains-induce-magnetism should contribute to the changes of the MS that associated with changes in crystalline strains at the previous discussion.

Simple Synthesis of Micrometer Fe3O4 Particles with Controlled Magnetic Behaviors

2011 ◽  
Vol 298 ◽  
pp. 273-277
Author(s):  
Gui Zhe Zhao ◽  
Xing Zhou ◽  
Ya Qing Liu ◽  
You Yi Sun
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Magnetic Properties ◽  
Fourier Transform ◽  
Room Temperature ◽  
High Saturation Magnetization ◽  
Vibrating Sample Magnetometer ◽  
Seeded Growth ◽  
Wide Range ◽  
Ft Ir

Fe3O4 particles were prepared by the co-precipitating method in the presence of polyethylene glycol (PEG). They were characterized by the Transmittance electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscope, which indicate the formation of spherical Fe3O4 particles with a wide range of sizes (up to 200 nm in radius) and the polydispersity of particle size below 20%. Furthermore, the magnetic properties of Fe3O4 particles were measured using a vibrating sample magnetometer (VSM), indicating that the particles possess high saturation magnetization at room temperature. These results are attributed that the Fe3O4 particles were directly coated with PEG in a seeded growth Sto¨ber process.

Effect of Temperature Synthesize on the Crystalline Structures and Magnetic Properties in Co-Precipitated Cobalt Ferrite Bismuth Nanoparticles

2020 ◽  
Vol 855 ◽  
pp. 3-8
Author(s):  
Santi Pratiwi ◽  
Utari ◽  
Budi Purnama
Keyword(s):  
Magnetic Properties ◽  
Fourier Transform ◽  
Saturation Magnetization ◽  
Cobalt Ferrite ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
Magnetic Characterization ◽  
X Ray ◽  
Bismuth Nanoparticles ◽  
Infra Red

The synthesis of CoBi0.15Fe1.85O4 obtained from cobalt ferrite doped by bismuth using the coprecipitation method was successfully carried out by varying the temperature of the titration. In this study the temperature of titration was used at 65°C, 75°C, 85°C, and 95°C. Annealing was then carried out at a temperature of 800°C for 5 hours. The results of the synthesis were then characterized using X-Ray Diffractometer (XRD), Fourier Transform Infra-Red (FTIR) and Vibrating Sample Magnetometer (VSM). The increase of the magnetic characterization i.e. the saturation magnetization increases and coercivity attribute the increase of the anisotropy crystalline.

Effect of Annealing temperature on the Structural and Magnetic Properties of TbxY3-xFe5O12(x = 0.0, 1.0, 2.0) Thin Films Prepared by Sol-Gel Process

2012 ◽  
Vol 501 ◽  
pp. 236-241 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah ◽  
Ramadan E. Shaiboub
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Garnet Phase ◽  
Sol Gel Process ◽  
Amorphous Structures

Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.

scholarly journals Changes of Pd Oxidation State in Pd/Al2O3 Catalysts Using Modulated Excitation DRIFTS

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 116
Author(s):  
Gian Luca Chiarello ◽  
Ye Lu ◽  
Miren Agote-Arán ◽  
Riccardo Pellegrini ◽  
Davide Ferri
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Oxidation State ◽  
Diffuse Reflectance ◽  
X Ray ◽  
Spectral Changes ◽  
Diffuse Reflectance Infrared ◽  
X Ray Absorption ◽  
Reversible Reduction

Infrared spectroscopy is typically not used to establish the oxidation state of metal-based catalysts. In this work, we show that the baseline of spectra collected in diffuse reflectance mode of a series of Pd/Al2O3 samples of increasing Pd content varies significantly and reversibly under alternate pulses of CO or H2 and O2. Moreover, these baseline changes are proportional to the Pd content in Pd/Al2O3 samples exhibiting comparable Pd particle size. Similar measurements by X-ray absorption spectroscopy on a different 2 wt.% Pd/Al2O3 confirm that the baseline changes reflect the reversible reduction-oxidation of Pd. Hence, we demonstrate that changes in oxidation state of metal-based catalysts can be determined using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and that this behavior is part of the spectral changes that are returned by experiments under operando conditions.

Annealing Effects on the Physical and Magnetic Properties of Tb1.5Y1.5Fe5O12 Films Nanoparticles Prepared by Sol-Gel Method

2013 ◽  
Vol 756 ◽  
pp. 91-98 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Annealing Temperature ◽  
Quartz Substrate ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Iron Garnet

Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900 °C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900°C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-raySpectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealingtemperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. Normal 0 21 false false false MS X-NONE X-NONE MicrosoftInternetExplorer4 Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900°C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900 °C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-ray Spectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealing temperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

scholarly journals Evolution of the Structural and Magnetic Properties of Bulk Fe61Co10B20W1Y8−XPtx Alloys through the Partial Substitution of Pt for Y

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4962
Author(s):  
Pawel Pietrusiewicz ◽  
Marcin Nabiałek ◽  
Bartłomiej Jeż
Keyword(s):  
Magnetic Properties ◽  
Small Addition ◽  
Partial Substitution ◽  
Vibrating Sample Magnetometer ◽  
Chemical Formula ◽  
X Ray ◽  
Saturation Magnetisation ◽  
Structural And Magnetic Properties ◽  
Structural Research ◽  
Scanning Electron

This paper presents the results of an investigation into rapidly quenched Fe-based alloys with the chemical formula: Fe61Co10B20W1Y8−xPtx (where x = 3, 4, 5). In these alloys, a small quantity of Pt was added, and the Y content was reduced concurrently. Samples of the aforementioned alloys were injection-cast in the form of plates with the dimensions: 0.5 mm × 10 mm × 10 mm. The resulting structure was examined using X-ray diffractometry (XRD), Mössbauer spectroscopy and scanning electron microscopy (SEM). The results of the structural research reveal that, with a small addition of Pt, areas rich in Pt and Y are created—in which Fe-Pt and Pt-Y compounds, with different crystallographic systems, are formed. It has also been shown that an increase in Pt content, at the expense of Y, contributed to the formation of fewer crystalline phases, i.e., it allowed a material with a more homogeneous structure to be obtained. Magnetic properties of the Fe61Co10B20W1Y8−xPtx (where x = 3, 4, 5) alloy samples were tested using a vibrating sample magnetometer (VSM). The magnetic properties of the investigated materials revealed that the saturation magnetisation increased with increasing Pt content, at the expense of Y. This effect is due to the occurrence of different proportions of crystalline magnetic phases within the volume of each alloy.

Sonochemical Co-Precipitation Synthesis of Gallic Acid-Modified Magnetite

2015 ◽  
Vol 1101 ◽  
pp. 286-289 ◽  
Author(s):  
Maya Rahmayanti ◽  
Sri Juari Santosa ◽  
Sutarno
Keyword(s):  
Magnetic Properties ◽  
Gallic Acid ◽  
Precipitation Method ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
One Step ◽  
The Fourier Transform ◽  
The One ◽  
Co Precipitation

Gallic acid-modified magnetites were synthesized by one and two-step reactions via the newly developed sonochemical co-precipitation method. The two-step reaction included the formation of magnetite powder and mixing the magnetite powder with gallic acid solution, while the one-step reaction did not go through the formation magnetite powder. The obtained gallic acid-modified magnetites were characterized by the Fourier Transform Infrared (FTIR) spectroscopy, the X-Ray Diffraction (XRD) and the Scanning Electron Microscopy (SEM). More over, the magnetic properties were studied by using a Vibrating Sample Magnetometer (VSM). The characterization results showed that there were differences in crystalinity, surface morphology and magnetic properties of products that were formed by one and two-step reactions.

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