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vibrating-sample-magnetometer
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Total 43 records
Solution Combustion Synthesis of Spinel-type (Cu,Co) 3O4 Nanopowder
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
In this study, nano-powders of copper-cobalt spinel (CuCo2O4) were fabricated by solution combustion synthesis (SCS) of Cu and Co nitrates with urea, glycine,acid citric and alanine. The method involved exothermic decomposition of viscous liquid nitrates and the fuel. Products which were synthesized by using this fuels contained less impurity constituents. Duo to low purity, other factors which have influence on synthesis process investigated and observed that pH have key role on process. X-ray diffraction (XRD) patterns gave crystal structure and the existing phases. Particle size distribution and morphology changes were studied by dynamic light scattering (DLS) and field emission scanning...
Design and Implementation of Vibrating Sample Magnetometer Based on Gradiometer RF SQUID
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
The aim of this project is design and implementation of the “gradiometer RF SQUID base Vibrating Sample Magnetometer (VSM)”. Different sections of the system have been designed such as pick up coils, vibration system and electronic circuits. The piezoelectric crystal has been concerned for vibration system. At the first step, we have implemented the basic VSM system. In the basic system, voltage induces in two series opposite pick up coils and its output is recognizable via electronic circuits. At the second phase of the project, the electronic circuits of basic VSM system have been replaced with the RF SQUID gradiometer and its electronic circuits. Afterwards, the sensitivity and the gain...
Critical Current Density Optimization of High-T_c Superconductor
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Fabrication of bulk superconductors with high critical current density widely has been studied because they have many applications, for example, Fault Current Limiter (SFCL), Superconducting Magnetic Energy Storage (SMES), and magnetic levitation. Providing pinning center by addings impurity into superconductor is usual and simple solution for increasing the superconductor critical current density. In this project we have fabricated superconductor YBCO bulk and optimized its critical current density. There are two major stream in this thesis, first design of Vibrating System Magnetization (VSM) for critical current measurements and then fabrication of YBCO bulk and optimization of its...
Study of nanocrystallization in FINEMET alloy by active screen plasma nitriding
, Article Journal of Alloys and Compounds ; Volume 491, Issue 1-2 , 2010 , Pages 487-494 ; 09258388 (ISSN) ; Madaah Hosseini, H. R ; Memarzadeh Lotfabad, E ; Roostaie, S ; Sharif University of Technology
2010
Abstract
The nanocrystallization process of amorphous Fe73.5Si13.5B9Nb3Cu 1 was investigated by active screen plasma nitriding (ASPN) treatment at temperatures ranging from 410 °C to 560 °C for 3 h in two gas mixtures of 75% N2-25% H2 and 25% N2-75% H2 at 5 mbar atmosphere. The amorphous ribbons were then annealed under vacuum at the same time and temperatures mentioned above. The structure of the samples was analyzed using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). Microhardness measurements, electrical resistivity and Vibrating Sample Magnetometer (VSM) were used to study mechanical, electrical and magnetic...
The effects of thickness on magnetic properties of FeCuNbSiB sputtered thin films
, Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3521-3525 ; 10263098 (ISSN) ; Celegato, F ; Tiberto, P ; Castellero, A ; Baricco, M ; Hosseini, H. R. M ; Sharif University of Technology
Abstract
Thin films of Fe73.1Cu1Nb3.1Si14.7B8.2 alloy with 200, 500, and 800 nm thicknesses have been deposited by RF sputtering. Their magnetic properties have been characterized using Alternating Gradient Field Magnetometer (AGFM) and Vibrating Sample Magnetometer (VSM). The effects of residual stresses investigated by nanoindentation experiments were conducted on the as-deposited samples. It is observed that the coercivity of as-deposited films is inversely proportional to the thickness in relation with the residual stress induced during sputtering. © 2017 Sharif University of Technology. All rights reserved
Performance of silver nanoparticle fixed on magnetic iron nanoparticles (Fe3O4−Ag) in water disinfection
, Article Micro and Nano Letters ; Volume 13, Issue 4 , April , 2018 , Pages 436-441 ; 17500443 (ISSN) ; Hassani, A. H ; Ahmad Panahi, H ; Borghei, M ; Sharif University of Technology
Institution of Engineering and Technology
2018
Abstract
Microbial contamination poses a serious threat to human health. The evaluation of alternative systems and their reliability for the treatment of water is essential. In this work, a new method for the deposit of more silver nanoparticles (AgNPs) on the external surface of Fe3O4 nanoparticles is presented. Fe3O4 nanoparticles were synthesised by chemical co-precipitation and were modified in two stages using 3-mercaptopropyl trimethoxysilane and grafting allyl glycidyl ether and N, N-dimethylacrylamide. Then, AgNPs were loaded onto the modified Fe3O4 to be used for water disinfection. The resulting nanoparticles were characterised by transmission electron microscopy, X-ray powder diffraction,...
PPI-dendrimer-functionalized magnetic metal-organic framework (fe3o4@mof@ppi) with high adsorption capacity for sustainable wastewater treatment
, Article ACS Applied Materials and Interfaces ; Volume 12, Issue 22 , 2020 , Pages 25294-25303 ; Hasanzadeh, M ; Nashtaei, M. S ; Rabbani, M ; Haji, A ; Hadavi Moghadam, B ; Sharif University of Technology
American Chemical Society
2020
Abstract
Herein, a magnetic zirconium-based metal-organic framework nanocomposite was synthesized by a simple solvothermal method and used as an adsorbent for the removal of direct and acid dyes from aqueous solution. To enhance its adsorption performance, poly(propyleneimine) dendrimer was used to functionalize the as-synthesized magnetic porous nanocomposite. The dendrimer-functionalized magnetic nanocomposite was characterized by field-emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibration sample magnetometer. The obtained results revealed the successful synthesis and functionalization of the...
L10 FePt Nanoparticles Processing with Applied Magnetic Field
, Article Journal of Inorganic and Organometallic Polymers and Materials ; Volume 23, Issue 4 , April , 2013 , Pages 881-887 ; 15741443 (ISSN) ; Khajehnezhad, A ; Dariani, R. S ; Akhavan, M ; Sharif University of Technology
2013
Abstract
Due to the strong magnetic anisotropy energy, the L10 FePt nanocrystals are considered as one of promising candidates for magnetic recording media with ultrahigh densities. The surfaces of Si and SiO2 wafers have been covered by FePt nanoparticles (NPs) and heated at 600 °C for 1 h to form the L10 phase. Bonding of NPs with the SiO2 surface in the presence of magnetic field during annealing process controls the L10 FePt NPs size and their uniform surface distribution. In the presence of perpendicular magnetic field to the surface, the size of NPs obtains up to 30 nm with coercivity of 5.8 kOe and in parallel magnetic field, the NPs size reaches to 45 nm with coercivity of 2.9 kOe. These...
Effect of Cysteine Substitutions on the Structural and Magnetic Properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine Nanocomposites
, Article Journal of Superconductivity and Novel Magnetism ; 2018 ; 15571939 (ISSN) ; Mehrani, K ; Madaah Hosseini, H. R ; Zare, K ; Sharif University of Technology
Springer New York LLC
2018
Abstract
We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of...
Effect of cysteine substitutions on the structural and magnetic properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine nanocomposites
, Article Journal of Superconductivity and Novel Magnetism ; Volume 32, Issue 5 , 2019 , Pages 1299-1306 ; 15571939 (ISSN) ; Mehrani, K ; Madaah Hosseini , H. R ; Zare, K ; Sharif University of Technology
Springer New York LLC
2019
Abstract
We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of...
Evaluations of structural, magnetic and various dielectric parameters of Ni-substituted Zn2W-type hexagonal ferrites for high frequency (1–6 GHz) applications
, Article Ceramics International ; Volume 45, Issue 18 , 2019 , Pages 24202-24211 ; 02728842 (ISSN) ; Shaukat, F ; Niaz Akhtar, M ; Ahmad, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The structural, electrical, magnetic and high frequency properties of Ni-substituted Zn2W-type hexagonal ferrites were investigated for microwave applications. Ferrite powders with chemical compositions Ba0 · 5Sr0.5NixZn2-xFe16O27 (where Ni-substitution was varied from 0.0 to 1.5 with a step size of 0.5) were prepared using sol-gel auto-combustion at 1300 °C. X-ray diffraction (XRD) analysis confirmed the single-phase hexagonal ferrite structure. The lengths of both the axis i.e. minor and major (a, c) obtained from hkl values of XRD peaks were decreased with Ni-substitution due to the difference in ionic radius of the substituted metal ions. DC electrical resistivity obtained by two-point...
Preparation and investigations on the thermal, structural and magnetic behavior of Co-Ce substituted Ni nanoferrites
, Article Materials Research Express ; Volume 6, Issue 11 , 2019 ; 20531591 (ISSN) ; Yasin, S ; Ramzan, N ; Iqbal, T ; Niaz Akhtar, M ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
Co-Ce doped Ni nanocrystalline ferrites having composition Ni0.8Ce0.2CoxFe2-xO4 with x = 0.00, 0.25, 0.50, 0.75, 1.00 were fabricated by sol gel auto combustion method. Synthesized samples were investigated by thermal gravimetric and differential thermal analysis (TGA-DTA), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis (EDX) and vibrating sample magnetometer (VSM) to study the phase, vibrational modes, structure, surface analysis and magnetic properties respectively. Structural parameters (lattice parameters, cell volume, crystallite size and micro strains) were also calculated from XRD recorded data....
Magnetic removal of crystal violet from aqueous solutions using polysaccharide-based magnetic nanocomposite hydrogels
, Article Polymer International ; Volume 62, Issue 7 , 2013 , Pages 1038-1044 ; 09598103 (ISSN) ; Hosseini, S. H ; Seidi, F ; Soleyman, R ; Sharif University of Technology
2013
Abstract
Magnetic Fe3O4@SiO2 starch-graft-poly(acrylic acid) (SPAA) nanocomposite hydrogels were prepared and used as absorbents for removal of crystal violet from aqueous solutions. Dynamic swelling, effect of contact time, absorption kinetics and nanocomposite hydrogel mass for removal of crystal violet dyes from aqueous solutions were studied. Fourier transform infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometer measurements were used for the characterization of the nanocomposite hydrogels. The nanocomposite hydrogels had high magnetic sensitivity under an external magnetic field, which allowed their magnetic separation from water, thus avoiding secondary...
Gold-Decorated 3D 2,6-diaminopyridine network: a robust catalyst for the bromination of aromatic compounds
, Article Industrial and Engineering Chemistry Research ; Volume 57, Issue 37 , 2018 , Pages 12314-12322 ; 08885885 (ISSN) ; Keshavarzi, N ; Hosseini, S. H ; Matloubi Moghaddam, F ; Sharif University of Technology
American Chemical Society
2018
Abstract
This article reports the synthesis of a magnetic heterogeneous catalyst through the decoration of gold ions onto the cross-linked polymeric nanocomposite from 2,6-diaminopyridine. The activity of the resulting catalyst was then evaluated in the bromination of aromatic compounds. The nitrogen rich support showed a high affinity to gold ions, and the measured content of Au was 0.76 mmol g-1. The structure of the catalyst was fully characterized by using Fourier-transform infrared spectroscopy, thermogravimetric analysis, atomic absorption spectroscopy, transmission electron microscopy, scanning electron microscope, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area...
Structural Rietveld refinement and magnetic features of prosademium (Pr) doped Cu nanocrystalline spinel ferrites
, Article Ceramics International ; Volume 45, Issue 8 , 2019 , Pages 10187-10195 ; 02728842 (ISSN) ; Babar, M ; Qamar, S ; ur Rehman, Z ; Azhar Khan, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Pr doped spinel nanoferrites having following composition Cu Pr x Fe 2-x O 4 (x = 0, 0.25, 0.50, 0.75, 1.00) were synthesized using sol-gel route. Prosademium (Pr) which is a rare earth metal was doped to tailor the properties of the Cu spinel nanoferrites. Characterization tools such as FTIR, XRD, FESEM and VSM were employed to investigate the phase, absorption bands, structure, microstructure and magnetic properties. FTIR was used to see the absorption bands and force constants of the Pr doped Cu spinel nanoferrites. Crystallite size, lattice parameters, cell volume and micro strains were determined from XRD data. Bulk density, X-ray density and porosity of the Pr doped Cu spinel...
Synthesis, morpho-structural properties, and catalytic performances of Pt-APA@Fe3O4/GO nanocomposite based on magnetical graphene in C–C coupling reactions and photoinactivation of E. coli
, Article Journal of Nanoparticle Research ; Volume 23, Issue 8 , 2021 ; 13880764 (ISSN) ; Sabounchei, S. J ; Yousefi, A ; Akhavan, O ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Herein, a novel Pt-APA composite (APA = pyridinium bromide salt) based on magnetic graphene oxide was synthesized and used as an effective catalyst. In this way, Fe3O4 nanoparticles are grown on graphene oxide (GO) nanosheets by a simple and practical method which creates a unique nanostructure (Fe3O4/GO) through dispersing uniformly among graphene nanosheets. The resulted Pt-APA composite was obtained via adding PtCl2 to an ethanol solution of Fe3O4/GO and α-keto stabilized pyridinium ylide in related conditions. The synthesized nanocomposite structure was identified using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive...
Effect of pH, citrate treatment and silane-coupling agent concentration on the magnetic, structural and surface properties of functionalized silica-coated iron oxide nanocomposite particles
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 44, Issue 3 , December , 2011 , Pages 618-627 ; 13869477 (ISSN) ; Yaghmaei, S ; Roostaazad, R ; Bardania, H ; Arpanaei, A ; Sharif University of Technology
Abstract
Superparamagnetic iron oxide nanoparticles were synthesized by coprecipitation of iron chloride salts at various pH values (9, 10, 11 and12) that were adjusted using an ammonia solution. Increasing the pH from 9 to 12 led to decreases in the size of iron oxide nanoparticles from 7.9±1.4 to 5±0.6 nm and the saturation magnetization (M s) from 82.73 to 67.14 emu/g, respectively, when analyzed with transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). X-ray diffraction patterns as well as M s values showed that magnetite is the dominantly synthesized phase in the examined pH values. Unmodified iron oxide nanoparticles were coated with silica via the hydrolysis and...
Structural and magnetic study of active screen plasma nitrided Fe 73.5Si13.5B9Nb3Cu1and Fe77Si11B9Nb2.4Cu0.6 ribbons
, Article Scientia Iranica ; Volume 17, Issue 1 F , 2010 , Pages 12-22 ; 10263098 (ISSN) ; Madaah Hosseini, H.R ; Asghari Shivaee, H ; Roostaie, S ; Sharif University of Technology
2010
Abstract
The comparative study of Active Screen Plasma Nitriding (ASPN) treatment of two Finemet-type alloys with the compositions of Fe73.5Si 13.5B9Nb3Cu1 and Fe 77Si11B9Nb2.4Cu0.6 was investigated in different temperatures ranging from 410°C to 56°C. Differential Scanning Calorimetry (DSC), X-Ray Diffractometery (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), electrical resistivity, microhardness measurements and magnetic characterization by a Vibrating Sample Magnetometer (VSM) were utilized to characterize the treated samples. The comparison of the DSC data for the alloys suggested that the smaller amount of Nb as a growth inhibitor shifted the crystallization...
Controlled microwave-assisted synthesis of ZnFe 2 O 4 nanoparticles and their catalytic activity for O-acylation of alcohol and phenol in acetic anhydride
, Article Scientia Iranica ; Volume 19, Issue 6 , December , 2012 , Pages 1597-1600 ; 10263098 (ISSN) ; Doulabi, M ; Saeidian, H ; Sharif University of Technology
2012
Abstract
ZnFe2O4 nanoparticles have been successfully prepared through a controlled microwave-assisted co-precipitation. X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) were used for the structural, morphological and magnetic investigation of the product. SEM micrographs of ZnFe2O4 nanopowder also reveal that nanoparticles have spherical shape. Average particle size was obtained as 12 nm from XRD. Catalytic activity of ZnFe2O4 nanopowder for O-acylation of alcohol and phenol has been investigated. A trace amount of ZnFe2O4 has been effectively used as a nanocatalyst for the acylation of alcohol and...
Magnetic/pH-sensitive κ-carrageenan/sodium alginate hydrogel nanocomposite beads: Preparation, swelling behavior, and drug delivery
, Article Journal of Biomaterials Science, Polymer Edition ; Vol. 25, issue. 17 , 2014 , p. 1891-1906 ; Rahmani, Z ; Karami, S ; Pourjavadi, A ; Sharif University of Technology
Abstract
This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K+/Ca2+ ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending...