Role of Particle Size on Structural and Magnetic Behavior of Nanocrystalline Cu-Ni Ferrite

2011 ◽  
Vol 171 ◽  
pp. 79-91 ◽  
Author(s):  
S.N. Dolia
Keyword(s):  
Particle Size ◽  
Saturation Magnetization ◽  
Fine Particles ◽  
Magnetic Moments ◽  
Magnetic Behavior ◽  
Nano Particles ◽  
Blocking Temperature ◽  
Precipitation Method ◽  
Xrd Patterns ◽  
Co Precipitation

Particle size has significant effect on the magnetic properties of fine particles. In this work, Cu0.2Ni0.8Fe2O4 nano-particles have been synthesized by the co-precipitation method. Different particle sizes were obtained by annealing the samples at various temperatures. The X-ray diffraction (XRD) patterns confirm the formation of cubic spinel structure. The particle size was found to enhance with increasing the annealing temperature. The saturation magnetization and the blocking temperature increase with particle size, which is a typical characteristic of the superparamagnetic behaviour. The dc magnetization measurements show that the samples are superparamagnetic above the blocking temperatures and the blocking temperature of the nanoparticles correlates with the size of the nanoparticles that is found to increase as the function of the particle size. The hysteresis curves show reduction in saturation magnetization in case of nanoparticles as compared to their bulk counterparts. This has been explained on the basis that the magnetic moments in the surface layers of a nanoparticle are in a state of frozen disorder. However, the saturation magnetization increases with particle size, which is a characteristic property of the single domain superparamagnetic particles.

Structural and Magnetic Behavior of Cobalt Doped Ba0.5Sr0.5Fe12O19 Nanoparticles Synthesized by Chemical Co-Precipitation Technique

2013 ◽  
Vol 274 ◽  
pp. 406-410 ◽  
Author(s):  
Jun Li Zhang ◽  
Ze Wu ◽  
Li Min Dong ◽  
Tao Jiang ◽  
Xian You Zhang
Keyword(s):  
Saturation Magnetization ◽  
Barium Ferrite ◽  
Single Phase ◽  
Intermediate Phase ◽  
Cobalt Content ◽  
Magnetic Behavior ◽  
Precipitation Method ◽  
Vibrating Sample Magnetometer ◽  
Xrd Patterns ◽  
Co Precipitation

Nanocrystalline M-type Co2+ substituted barium hexaferrites samples having generic formula barium Ba0.5Sr0.5Fe12-xCoxO19 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were synthesized by chemical co-precipitation method. The sintered samples were characterized by XRD, SEM and VSM techniques. All the XRD patterns showed the single phase of the magnetoplumbite barium ferrite without other intermediate phase. The lattice parameters (a and c) obtained from XRD data decreases with increase in cobalt content x. The magnetic behavior of the samples was studied using vibrating sample magnetometer technique. The saturation magnetization (Ms) first increases reaching a maximum of 63.684 emu/g at x=0.4, and then decreases. The coercivity (Hc) decreases with increase in cobalt content x.

scholarly journals Study of Structural and Magnetic Properties, Trivalent Cation Substitution of Cobalt base Spinel Ferrites CoCr0.04LaxFe1.96-xO4 (0 ≤ x ≤ 0.12)

2020 ◽  
Author(s):  
G. MUSTAFA ◽  
Z. FAROOQ ◽  
M.R. AHMAD ◽  
H. ANWAR ◽  
H. AKHTAR ◽  
...  
Keyword(s):  
Saturation Magnetization ◽  
Research Work ◽  
Magnetic Behavior ◽  
Spinel Ferrites ◽  
Precipitation Method ◽  
Trivalent Cation ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Morphological Studies ◽  
Co Precipitation

Abstract In this research work a series of polycrystalline trivalent cation (Cr3+, La3+) substituted cobalt ferrite with general formula CoCr0.04LaxFe1.96-xO4 where 0.00 ≤ x ≤ 0.12 (in steps of 0.02) was synthesized using co-precipitation method and were sintered at 900°C for 6 hours. The phase identification and confirmation of the structure were confirmed employing the X-ray diffraction (XRD) and FTIR techniques. The size of crystallite was found on average, in the range of 53-106 nano-meters. FTIR results confirmed spinel ferrites structure. Moreover the morphological studies were observed through SEM. The elemental analysis of the samples was done by EDX while, I-V characterization of the represented sample was recorded using two probe method. The measured electrical resistivity of materials increased as dopant content increased. The magnetic behavior of the materials was studied using vibrating sample magnetometer (VSM). The saturation magnetization values and magnetic coercivity values decreased with the increase of La3+ concentration. The saturation magnetization (Ms) of the ferrite materials decreased with the reduction of size.

Magnetic behavior of coated superparamagnetic iron oxide nanoparticles in ferrofluids

2001 ◽  
Vol 676 ◽  
Author(s):  
W. Voit ◽  
D. K. Kim ◽  
W. Zapka ◽  
M. Muhammed ◽  
K. V. Rao
Keyword(s):  
Particle Size ◽  
Iron Oxide ◽  
Superparamagnetic Iron Oxide ◽  
Magnetic Behavior ◽  
Blocking Temperature ◽  
Iron Oxide Particles ◽  
Physical Particle ◽  
Superparamagnetic Iron Oxide Particles ◽  
Oxide Particles ◽  
Co Precipitation

ABSTRACTWe present a study on the magnetic behavior of nanosized iron oxide particles coated with different surfactants (sodium oleate, PVA and starch) in a ferrofluid. The effect of the coating material, and different particle concentrations in the ferrofluid have been magnetically investigated to determine the effective magnetic particle size and possible interaction. The superparamagnetic iron oxide particles, synthesized by a controlled co-precipitation technique, are found to contain magnetite (Fe3O4) as a main phase with a narrow physical particle size distribution between 6 and 8 nm. The mean effective magnetic size of the particles in different ferrofluid systems are estimated to be around 4-5 nm which is smaller than the physical particle size. On a 10% dilution in the starch coated ferrofluid we observe a decrease in the blocking temperature.

Microstructure and Magnetic properties of ferrite nanoparticles synthesized by  Co-precipitation method

2021 ◽  
Author(s):  
R. Sagayaraj ◽  
S.Aravazhi ◽  
G. Chandrasekaran
Keyword(s):  
Particle Size ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Precipitation Method ◽  
Mixed Spinel ◽  
Spinel Composition ◽  
Li Ion ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Microstructure And Magnetic Properties

Abstract In the current research, Cu0.5Co0.3Mo0.2Fe2O4 mixed ferrite nanoparticles have been synthesized using Co-precipitation method. XRD patterns show the development of polyphasic copper, cobalt and molybdenum mixed spinel composition. The particle size of ferrite system is 16nm and they are nanoparticles. The lattice constant was determined to be 8.368 Å used for the highest peak (311). FTIR spectroscopy shows the lower octahedral and higher tetrahedral frequency alignment of ions in the spinel ferrite leading to the octahedral 550 cm− 1 and the tetrahedral 471 cm− 1 vibration modes. TEM micrographs showed spherical morphology and their particle size less than 50 nm, which correlated XRD crystallite size. VSM shows excellent ferrimagnetic properties because of higher coercivity (985.29 G). These higher coercivity materials can make cathode content for Li-ion batteries.

Study on Preparation and Performance of MRF for Torque Transmission

2011 ◽  
Vol 328-330 ◽  
pp. 1057-1061
Author(s):  
Zi Xin Dong ◽  
Chu Wen Guo ◽  
You Fu Hou ◽  
Qing Rui Meng ◽  
Fei Hu Li
Keyword(s):  
Saturation Magnetization ◽  
Orthogonal Test ◽  
Nano Particles ◽  
Practical Significance ◽  
Precipitation Method ◽  
Optimal Method ◽  
Amount Of Substance ◽  
Peg 4000 ◽  
Torque Transmission ◽  
Co Precipitation

Based on the requirements of torque transmission for stability and saturation magnetization of magnetorheological fluid (MRF), an orthogonal test was designed to arrange for the preparation of MRF. MRF was prepared by chemical co-precipitation method, in which Fe3O4 nano-particles were coated with polyethylene glycol(PEG-4000). The size and distribution of particles were observed by transmission electron microscope (TEM). The saturation magnetization was measured by vibrating sample magnetometer(VSM). Through analysis of variance of orthogonal test,an optimal method for preparing a highly stable and saturation magnetization MRF was summarized. Four main parameters in preparation of MRF were discussed, including the rate of amount of substance between Fe2+and Fe3+, the rate of amount of substance between PEG-4000 and Fe2+, reaction time and the reaction temperature. It has important practical significance on the study of magnetorheological transmission device.

STRUCTURE, MORPHOLOGICAL, MAGNETIC AND OPTICAL PROPERTIES OF CuxMg1-xFe2O4 (x = 0, 0.5, 1) NANO FERRITES SYNTHESIZED BY CO-PRECIPITATION METHOD

2021 ◽  
pp. 46-54
Author(s):  
Chinh
Keyword(s):  
Saturation Magnetization ◽  
Spinel Structure ◽  
Single Phase ◽  
Secondary Phase ◽  
Ferromagnetic Material ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns ◽  
Co Precipitation

CuxMg1.xFe2O4 nanoparticles were successfully synthesized by co-precipitation. The samples were calcined at 900 oC for 3 h and X-ray diffraction analysis showed that Cu0.5Mg0.5Fe2O4 had a single phase cubic spinel structure, while formation of secondary phase of Fe2O3 was observed in XRD patterns of CuFe2O4, MgFe2O4. The saturation magnetization (Ms) of Cu0.5Mg0.5Fe2O4 is in between the saturation magnetization values of CuFe2O4 and MgFe2O4 nanoparticles, CuFe2O4 is a ferromagnetic material, while MgFe2O4 and Cu0.5Mg0.5Fe2O4 show superparamagnetic behavior. The synthesized spinel ferrites were fully characterized using scanning electron microscopy (SEM), FTIR spectroscopy, energy dispersive spectroscopy (EDS) and UV-vis spectrophotometry.

Magnetic and dielectric properties study of cobalt ferrite nanoparticles synthesized by co-precipitation method

2011 ◽  
Vol 1368 ◽  
Author(s):  
M. Krishna Surendra ◽  
D. Kannan ◽  
M. S. Ramachandra Rao
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Saturation Magnetization ◽  
Cobalt Ferrite ◽  
Ferrite Nanoparticles ◽  
Precipitation Method ◽  
Co Precipitation ◽  
Inert Layer

Abstract:Cobalt ferrite nanoparticles were prepared by co-precipitation method and were heat treated at 100 oC, 200 oC, 400 oC and 600 oC for 2 h to increase the particle size. Phase purity of samples was confirmed by X-ray diffraction. Scherrer formula calculations showed crystallite size varied from 12 to 24 nm when heated from 100 oC to 600 oC. Transmission electron microscopy reveals a uniform and narrow particle size distribution about 12 nm for as-prepared cobalt ferrite particles. Room temperature saturation magnetization was found to vary from 40.8 to 67.0 emu/g as the particle size increased from12 nm to 24 nm. Increase in saturation magnetization with increase in particle size was attributed to the presence of magnetic inert layer on the surface of nanoparticles. Inert layer thickness calculated at 10 K and 300 K was 6 Å and 11 Å respectively. The dielectric properties ε’, tanδ, Z and θ have been studied as a function of frequency and particles size. For the 12 nm grain size, the dielectric constant is one order higher than that of bulk cobalt ferrite. Increase in the grain size showed an increase in the dielectric constant. The increase in the conductivity with grain size is mainly due to the grain size effects. The present study shows that the dielectric properties can be tailor-made to suit the requirement of a particular application by controlling the grain size.

The effect of Tin additionon on Structural and magnetic properties of the stannoferrite Li0.5+0.5XFe2.5-1.5XSnXO4

2016 ◽  
Vol 12 (3) ◽  
pp. 4307-4321 ◽  
Author(s):  
Ahmed Hassan Ibrahim ◽  
Yehia Abbas
Keyword(s):  
Particle Size ◽  
Fine Particles ◽  
Magnetic Moments ◽  
Lithium Ferrite ◽  
Tem Analysis ◽  
Weiss Temperature ◽  
X Ray ◽  
Two Phases ◽  
Nanocrystalline Ferrite ◽  
20 Nm

The physical properties of ferrites are verysensitive to microstructure, which in turn critically dependson the manufacturing process.Nanocrystalline Lithium Stannoferrite system Li0.5+0.5XFe2.5-1.5XSnXO4,X= (0, 0.2, 0.4, 0.6, 0.8 and 1.0) fine particles were successfully prepared by double sintering ceramic technique at pre-sintering temperature of 500oC for 3 h andthepre-sintered material was crushed and sintered finally in air at 1000oC.The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction (XRD) and the Rietveld method.The refinement results showed that the nanocrystalline ferrite has a two phases of ordered and disordered phases for polymorphous lithium Stannoferrite.The particle size of as obtained samples were found to be ~20 nm through TEM that increases up to ~ 85 nmand isdependent on the annealing temperature. TEM micrograph reveals that the grains of sample are spherical in shape. (TEM) analysis confirmed the X-ray results.The particle size of stannic substituted lithium ferrite fine particle obtained from the XRD using Scherrer equation.Magneticmeasurements obtained from lake shore’s vibrating sample magnetometer (VSM), saturation magnetization ofordered LiFe5O8 was found to be (57.829 emu/g) which was lower than disordered LiFe5O8(62.848 emu/g).Theinterplay between superexchange interactions of Fe3+ ions at A and B sublattices gives rise to ferrimagnetic ordering of magnetic moments,with a high Curie-Weiss temperature (TCW ~ 900 K).

scholarly journals Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 341
Author(s):  
Tien Hiep Nguyen ◽  
Gopalu Karunakaran ◽  
Yu.V. Konyukhov ◽  
Nguyen Van Minh ◽  
D.Yu. Karpenkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Reduction Temperature ◽  
Fe Content ◽  
Magnetic Features ◽  
Co Precipitation

This paper presents the synthesis of Fe–Co–Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe–Co–Ni nanocomposites. The initial hydroxides of Fe–Co–Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300–500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6–192.5 Am2/kg, Mr = 0.4–39.7 Am2/kg, Mr/Ms = 0.02–0.32, and HcM = 4.72–60.68 kA/m by regulating the composition and reduction temperature of the Fe–Co–Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe–Co–Ni ternary system phase content and magnetic properties was evaluated. The Fe–Co–Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

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