scholarly journals Structural and Magnetic Investigations of Silica coated Cobalt- Ferrite Nanocomposites

2018 ◽  
Vol 34 (4) ◽  
pp. 2060-2067 ◽  
Author(s):  
Meenakshi Bansal ◽  
Praveen Aghamkar ◽  
Dharamvir Singh Ahlawat
Keyword(s):  
Room Temperature ◽  
Cobalt Ferrite ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
Metal Nitrates ◽  
Heating Effects ◽  
Heat Treated ◽  
Strong Relation ◽  
Sio2 Nanocomposites ◽  
Co Precipitation

Silica coated cobalt ferrite (CoFe2O4:SiO2) nanocomposites were synthesized by co-precipitation technique using metal nitrates as precursors. The as-prepared sample has been further heat treated at 250°C, 500°C,750°C and 1000°C. Their structure and morphology related properties were desirably investigated by XRD, FTIR, TEM characterization techniques. Further, with the help of vibrating sample magnetometer (VSM) the magnetic properties have been successfully analysed. Furthermore, the structure and magnetism related properties of these nanocomposites are also understood with heating effects. With increasing calcinations temperature, crystallite size of CoFe2O4:SiO2 nanocomposites was also found to increase. The room temperature magnetic measurements have shown a strong relation of saturation magnetization, retentivity and coercivity with annealing temperature.

X-Ray Diffraction Analysis on Crystallite Development of Nanostructured Aluminium

2006 ◽  
Vol 118 ◽  
pp. 53-58
Author(s):  
Elisabeth Meijer ◽  
Nicholas Armstrong ◽  
Wing Yiu Yeung
Keyword(s):  
Crystallite Size ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Equal Channel Angular Extrusion ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Heat Treated ◽  
Diffraction Peaks

This study is to investigate the crystallite development in nanostructured aluminium using x-ray line broadening analysis. Nanostructured aluminium was produced by equal channel angular extrusion at room temperature to a total deformation strain of ~17. Samples of the extruded metal were then heat treated at temperatures up to 300oC. High order diffraction peaks were obtained using Mo radiation and the integral breadth was determined. It was found that as the annealing temperature increased, the integral breadth of the peak reflections decreased. By establishing the modified Williamson-Hall plots (integral breadth vs contract factor) after instrumental correction, it was determined that the crystallite size of the metal was maintained ~80 nm at 100oC. As the annealing temperature increased to 200oC, the crystallite size increased to ~118 nm. With increasing annealing temperature, the hardness of the metal decreased from ~60 HV to ~45 HV.

scholarly journals Deposition of Lu-Fe-O thin films on silica glass substrates by MOCVD

2020 ◽  
Vol 233 ◽  
pp. 05006
Author(s):  
A.F. Cardoso ◽  
A.A. Bassou ◽  
V.S. Amaral ◽  
J.R. Fernandes ◽  
P.B. Tavares
Keyword(s):  
Thin Films ◽  
Silica Glass ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
Garnet Phase ◽  
Glass Substrates ◽  
Post Annealing ◽  
Post Annealing Temperature ◽  
Deposition Conditions

Thin films of the Lu-Fe-O system were deposited by aerosol assisted MOCVD on silica glass substrates. Hexagonal h-LuFeO3, garnet Lu3Fe5O12, perovskite o-LuFeO3 or hematite Fe2O3 phases were obtained, depending on the thermodynamic deposition conditions or post annealing temperature. Magnetic measurements confirm the ferromagnetic behaviour at room temperature of the thin films with garnet phase. An indirect bandgap of 1.78 eV was measured.

Magneto-Opto Electronic Applications of Conductive and Room Temperature Ferromagnetic (Al, Mn) Co-Doped ZnO Particles with Visible Emission

2020 ◽  
Vol 20 (6) ◽  
pp. 3913-3918 ◽  
Author(s):  
Divya Rehani ◽  
Swati Bishnoi ◽  
Manish Saxena ◽  
Shailesh Narain Sharma
Keyword(s):  
Room Temperature ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
Hexagonal Wurtzite Structure ◽  
Solid State Reaction Method ◽  
Ferromagnetic Behavior ◽  
Maximum Conductivity ◽  
Doped Zno ◽  
Mn Doped ◽  
Co Doped

The Mn, Al co-doped ZnO samples were synthesized using solid-state reaction method and were annealed in furnace at 300 °C, 600 °C and 900°C temperature. All the samples prepared were investigated in detail for analysis of their structural, morphological, optical, magnetic and electrical behavior. The XRD data confirmed the hexagonal wurtzite structure of pristine, Mn doped and Al, Mn co-doped ZnO. For morphological investigation SEM and TEM techniques were employed. The PL properties of the ZnO:Mn, Al sample revealed emission in the blue region (415–438 nm). Furthermore, IV studies were carried out to examine the conductivity of the ZnO:Mn, Al samples and maximum conductivity was found in the sample with 5% Al doping and annealing temperature 600 °C. The magnetic measurements revealed room temperature ferromagnetic behavior in the optimized ZnO:Mn, Al sample annealed at 600 °C which indicates its suitability for Magneto-Opto Electronic Applications.

Microstructural and Magnetic Studies on Calcined Ni-Zn Ferrite Powders Prepared by Chemical Co-Precipitation Method

2011 ◽  
Vol 264-265 ◽  
pp. 524-529
Author(s):  
I.Z. Rahman ◽  
T.T. Ahmed
Keyword(s):  
Room Temperature ◽  
Magnetic Measurements ◽  
Precipitation Method ◽  
Particle Sizes ◽  
Magnetic Studies ◽  
Zn Ferrite ◽  
Different Temperatures ◽  
Bet Technique ◽  
Co Precipitation ◽  
Cation Distributions

In this paper, we report on structural and magnetic properties of NiZn ferrite powders prepared by chemical co-precipitation method and calcined at different temperatures. Structural, topological and compositional analyses were performed by XRD, SEM, AFM and EDX techniques. The cation distributions in Ni0.8Zn0.2Fe2O4 ferrites were investigated by XPS (Al K radiation: h=1486.6 eV). Particle sizes were measured using AFM techniques and results were compared with BET technique and magnetic measurements were carried out using a vibrating sample magnetometer at room temperature.

scholarly journals The Effect of Sr-CoFe2O4 Nanoparticles with Different Particles Sized as Additives in CIP-Based Magnetorheological Fluid

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3684
Author(s):  
Kacuk Cikal Nugroho ◽  
Ubaidillah Ubaidillah ◽  
Retna Arilasita ◽  
Margono Margono ◽  
Bambang Hari Priyambodo ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cobalt Ferrite ◽  
Iron Particle ◽  
Magnetorheological Fluid ◽  
Particle Sizes ◽  
Cofe2o4 Nanoparticles ◽  
Calcination Temperatures ◽  
Grain Sizes ◽  
Co Precipitation ◽  
Nanoparticle Additives

This study investigated the effect of adding strontium (Sr)-doped cobalt ferrite (CoFe2O4) nanoparticles in carbonyl iron particle (CIP)-based magnetorheological fluids (MRFs). Sr-CoFe2O4 nanoparticles were fabricated at different particle sizes using co-precipitation at calcination temperatures of 300 and 400 °C. Field emission scanning electron microscopy (FESEM) was used to evaluate the morphology of the Sr-CoFe2O4 nanoparticles, which were found to be spherical. The average grain sizes were 71–91 nm and 118–157 nm for nanoparticles that had been calcinated at 300 and 400 °C, respectively. As such, higher calcination temperatures were found to produce larger-sized Sr-CoFe2O4 nanoparticles. To investigate the rheological effects that Sr-CoFe2O4 nanoparticles have on CIP-based MRF, three MRF samples were prepared: (1) CIP-based MRF without nanoparticle additives (CIP-based MRF), (2) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 300 °C (MRF CIP+Sr-CoFe2O4-T300), and (3) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 400 °C (MRF CIP+Sr-CoFe2O4-T400). The rheological properties of these MRF samples were then observed at room temperature using a rheometer with a parallel plate at a gap of 1 mm. Dispersion stability tests were also performed to determine the sedimentation ratio of the three CIP-based MRF samples.

scholarly journals Room Temperature Magnetic Memory Effect in Cluster-Glassy Fe-Doped NiO Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1318 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Tai-Yue Li ◽  
B. Vijaya Kumar ◽  
P. Muralidhar Reddy ◽  
Jen-Chih Peng ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Oxide System ◽  
Precipitation Method ◽  
Magnetic Memory ◽  
Nio Nanoparticles ◽  
Magnetic Anisotropy Energy ◽  
Spintronic Devices ◽  
Co Precipitation

The Fe-doped NiO nanoparticles that were synthesized using a co-precipitation method are characterized by enhanced room-temperature ferromagnetic property evident from magnetic measurements. Neutron powder diffraction experiments suggested an increment of the magnetic moment of 3d ions in the nanoparticles as a function of Fe-concentration. The temperature, time, and field-dependent magnetization measurements show that the effect of Fe-doping in NiO has enhanced the intraparticle interactions due to formed defect clusters. The intraparticle interactions are proposed to bring additional magnetic anisotropy energy barriers that affect the overall magnetic moment relaxation process and emerging as room temperature magnetic memory. The outcome of this study is attractive for the future development of the room temperature ferromagnetic oxide system to facilitate the integration of spintronic devices and understanding of their fundamental physics.

Coercivity in nanostructured FeCo-based powders prepared by mechanical alloying

2006 ◽  
Vol 980 ◽  
Author(s):  
Qi Zeng ◽  
Ian Baker ◽  
Virginia McCreary ◽  
Zhicheng Yan
Keyword(s):  
Mechanical Alloying ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Magnetic Interaction ◽  
Magnetic Exchange ◽  
Grain Sizes ◽  
Heat Treated ◽  
Powder Particles ◽  
The Individual ◽  
Exchange Length

AbstractFeCo-based nanostructured powders were prepared by mechanical alloying and subsequently heat treated in an attempt to reduce their coercivity, HC. Although the powders had grain sizes smaller than the magnetic exchange length, a low HC, as expected from Herzer's model, did not occur. The results of magnetic measurements on dilute and concentrated samples of the powder, as well as measurements of the temperature dependence of the magnetic properties from 10-300 K, indicate that the degree of magnetic interaction between the individual powder particles determines the relatively high HC of 10-20Oe at room temperature.

Effects of annealing temperature on structural and luminescence properties of CdMoO4:Dy3+ phosphor synthesized at room temperature by co-precipitation method

2020 ◽  
Vol 102 ◽  
pp. 106172 ◽  
Author(s):  
N. Premjit Singh ◽  
N. Ramananda Singh ◽  
Y. Rangeela Devi ◽  
Brojendro Singh Sh ◽  
Th. David Singh ◽  
...  
Keyword(s):  
Room Temperature ◽  
Annealing Temperature ◽  
Luminescence Properties ◽  
Precipitation Method ◽  
Co Precipitation

Evolution of Magnetism in CaO-SiO2-P2O5-Na2O-Fe2O3 Bioglass Ceramics

2008 ◽  
Vol 587-588 ◽  
pp. 171-174
Author(s):  
Rajendra Kumar Singh ◽  
A. Perumal ◽  
Govind P. Kothiyal ◽  
A. Srinivasan
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Structural Investigation ◽  
Magnetic Measurements ◽  
Magnetic Behavior ◽  
Soft Magnetic Materials ◽  
Soft Magnetic ◽  
Melt Quenching ◽  
Heat Treated ◽  
Magnetite Phase

We report the evolution of magnetism in bioglass ceramics 41CaO.(52-x)SiO2.4P2O5. xFe2O3.3Na2O (2 ≤ x ≤ 10 mole % Fe2O3) prepared by melt quenching technique followed by heat treatment at 1050 oC. The structural investigation revealed the presence of magnetite phase in the heat treated samples with x ≥ 2 mole % Fe2O3. Room temperature magnetic measurements showed a very weak ferrimagnetic behaviour for the sample with x = 2 mole % of Fe2O3. Samples with x > 2 mole % of Fe2O3 exhibited magnetic behavior similar to soft magnetic materials with low coercivity. The evolution of magnetic properties in these samples as a function of Fe2O3 molar concentration is correlated with the amount of magnetite phase present in them.

scholarly journals Investigation of annealing temperature on the synthesis of zincite doped cobalt ferrite using Rietveld refinement

2021 ◽  
Vol 2070 (1) ◽  
pp. 012091
Author(s):  
Himanshu Bedi ◽  
Sunil Rohilla ◽  
Nitika Chaudhary
Keyword(s):  
Zinc Oxide ◽  
Rietveld Refinement ◽  
Composite Powder ◽  
Cobalt Ferrite ◽  
Annealing Temperature ◽  
Crystalline Phases ◽  
Space Group ◽  
Precipitation Technique ◽  
Co Precipitation ◽  
R Factors

Abstract Co-precipitation technique is used for preparing the composites of CoFe2O4/VZnO. The effect on the variation on the size of the crystals of CoFe2O4 is studied by varying the annealing temperature over the range from 500°C to 900°C. The structure of composite powder obtained after annealing was studied by Rietveld refinement and XRD. The estimation of the crystalline phases of the sample is done by XRD though Rietveld refinement. The space group and structure of zinc oxide was observed as P63mc(186) and hexagonal while that for the cobalt ferrite was Fd3m(227) and cubic. The values of all R factors was calculated and the effect of annealing temperature on the size of the crystal was discussed.

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