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vibrating-sample-magnetometer
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Effects of Ce–Co substitution on structural, magnetic and dielectric properties of M-type barium hexaferrite nanoparticles synthetized by sol–gel auto-combustion route
, Article Journal of Materials Science: Materials in Electronics ; Volume 26, Issue 4 , 2015 , Pages 2134-2144 ; 09574522 (ISSN) ; Nemati, A ; Sharif University of Technology
Springer New York LLC
2015
Abstract
M-type Ce–Co substituted barium hexaferrite nanoparticles were synthesized by sol–gel auto-combustion route. The general formula of ferrites was Ba1−xCexFe12−xCoxO19 in which the x was considered to be: x = 0, 0.1, 0.2, and 0.3. The formed phases in the samples were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, Mössbauer spectroscopy and vibrating sample magnetometer. The results indicated that an increase in substitutional ion amount caused to decrease vibration frequencies of Fe–O band in the tetrahedral site due to the substitution of heavier Co2+ ion for Fe3+ ion in the tetrahedral site. Moreover, some of Ce3+ ions was transformed to Ce4+ and...
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...
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...
Effect of synthesis method on magnetic and thermal properties of polyvinylidene fluoride/Fe3O4 nanocomposites
, Article Journal of Reinforced Plastics and Composites ; Volume 32, Issue 14 , 2013 , Pages 1044-1051 ; 07316844 (ISSN) ; Hadi, M ; Sharif University of Technology
2013
Abstract
Polyvinylidene fluoride magnetic nanocomposite films were prepared by solution casting using two types of magnetic nanoparticles: (a) magnetic nanoparticles synthesized by co-precipitation method using oleic acid as a coating agent and (b) Fe3O4 nanoparticles prepared by hydrolysis method without using a coating agent. Dynamic light scattering measurements showed mean diameters of 135 and 46 nm in co-precipitation and hydrolysis methods, respectively. Scanning electron microscopy showed that the magnetic nanoparticles were uniformly dispersed inside the polymer matrix. X-ray diffraction confirmed that Fe3O4 nanoparticles induced nucleation of β- crystalline phase in the matrix polymer. The...
Facile fabrication and characterization of amino-functionalized Fe 3O4 cluster@SiO2 core/shell nanocomposite spheres
, Article Materials Research Bulletin ; Volume 48, Issue 6 , 2013 , Pages 2023-2028 ; 00255408 (ISSN) ; Kazemeini, M ; Arpanaei, A ; Sharif University of Technology
2013
Abstract
We developed a modified straightforward method for the fabrication of uniformly sized silica-coated magnetite clusters core/shell type nanocomposite particles. Proposed simple one-step processing method permits quick production of materials in high yield. The structural, surface, and magnetic characteristics of the nanocomposite particles were investigated by transmission electron microscopy (TEM), scanning electron microscope (SEM), powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Fourier-transform infrared (FTIR). The sphere-shaped particles almost have the average diameter of 120 nm, with a magnetic cluster core of 80 ± 15 nm, and a silica shell of 25 ± 10 nm...
Catalytic activity of the spinel ferrite nanocrystals on the growth of carbon nanotubes
, Article Journal of Superconductivity and Novel Magnetism ; Volume 26, Issue 2 , 2013 , Pages 429-435 ; 15571939 (ISSN) ; Daadmehr, V ; Rezakhani, A. T ; Shahbaz Tehrani, F ; Aghakhani, F ; Gholipour, S ; Sharif University of Technology
2013
Abstract
We prepared three ferrite nanocatalysts: (i) copper ferrite (CuFe 2O4) (ii) ferrite where cobalt was substituted by nickel (Nix Co1-x Fe2O4, with x=0, 0.2, 0.4, 0.6), and (iii) ferrite where nickel was substituted by zinc (Zn y Ni1-y Fe2O4 with y=1, 0.7, 0.5, 0.3), by the sol-gel method. The X-ray diffraction patterns show that the ferrite samples have been crystallized in the cubic spinel structural phase. We obtained the size of grains by field emission scanning electron microscopy images and their magnetic properties by vibrating sample magnetometer. Next, carbon nanotubes were grown on these nanocatalysts by the catalytic chemical vapor deposition method. We show that the catalytic...
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...
Optimized design and implementation of low-cost, sensitive and versatile vibrating sample magnetometer
, Article ICEE 2012 - 20th Iranian Conference on Electrical Engineering, 15 May 2012 through 17 May 2012 ; May , 2012 , Pages 202-205 ; 9781467311489 (ISBN) ; Khiabani, S ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
2012
Abstract
Geometry of different electromagnetic parts of Vibrating Sample Magnetometer (VSM) is a major factor of VSM output voltage. In this paper design, geometry optimization and implementation of a sensitive, versatile and relatively inexpensive VSM system has been described. Considering all effective geometrical parameters in the system output voltage, the induced voltage in the pick-up coils has been obtained analytically and the geometry of the pick-up coils has been optimized for maximum output induced voltage. Two opposite series of pick-up coils, piezoelectric based vibration system and required electronic circuits have been designed and the VSM system has been implemented. The implemented...
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...
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...
Effect of hydrogen reduction on microstructure and magnetic properties of mechanochemically synthesized Fe-16.5Ni-16.5Co nano-powder
, Article Journal of Magnetism and Magnetic Materials ; Volume 321, Issue 18 , 2009 , Pages 2729-2732 ; 03048853 (ISSN) ; Yoozbashizadeh, H ; Sadrnezhaad, S. K ; Sharif University of Technology
2009
Abstract
Most recent findings on structural and magnetic properties of Fe-Ni-Co nano-powders produced by mechanical alloying and subsequent low-temperature hydrogen reduction are presented in this paper. At 300 rpm, with ball to powder weight ratio of 20, single phase nickel-cobalt ferrite is mechanically synthesized for 50 h. The as-milled powder is then subjected to 1 h hydrogen reduction at 700 °C. Hydrogen reduction results in the formation of Fe-16.5%Ni-16.5%Co nano-powders. The phases of the powders are identified by X-ray diffraction (XRD) utilizing Cu Kα radiation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to study the morphology and the average...
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...
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...
Nano-magnetic poly (vinyl alcohol) hydrogels
, Article Advanced Materials Research ; Volume 829 , 2014 , Pages 539-543 ; ISSN: 10226680 ; ISBN: 9783037859070 ; Frounchi, M ; Dadbin, S ; Sharif University of Technology
Abstract
Surface modified magnetic nanoparticles (M-NPs) were synthetized and stabilized in poly (vinylalcohol) solution. The solutions with various magnetic nanoparticles contents were gammairradiated and magnetic poly (vinyl-alcohol) (M-PVA) hydrogels were synthesized. The magnetic hydrogels and also the un-irradiated magnetic poly (vinyl alcohol) nanocomposite films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR) and mechanical measurement. The M-NPs were uniformly dispersed in the polymer matrix due to a strong interaction between the surface-modified M-NPs and polymer matrix....
Effect of Ti-Zn substitution on structural, magnetic and microwave absorption characteristics of strontium hexaferrite
, Article Journal of Alloys and Compounds ; Vol. 583, issue , 2014 , p. 325-328 ; Ghasemi, A ; Nemati, A ; Azami Ghadikolaei, M ; Paimozd, E ; Sharif University of Technology
Abstract
SrFe12-xTix/2Zn x/2O19 (x = 0-2.5) powders were synthesized by use of chlorides through co-precipitation method. The obtained powders were then milled by high energy ball mill to crash hard agglomerates and achieve nanoparticles. In order to evaluate microwave absorption versus frequency, composites including ferrite, as a filler, and matrix of polyvinylchloride (PVC) with weight ratio of 70% ferrite were prepared. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA) were employed to study the structural, magnetic and microwave absorption properties...
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...
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...
Phase formation and change of magnetic properties in mechanical alloyed Ni0.5Co0.5Fe2O4 by annealing
, Article Journal of Magnetism and Magnetic Materials ; Volume 322, Issue 1 , 2010 , Pages 56-59 ; 03048853 (ISSN) ; Yoozbashizadeh, H ; Yourdkhani, A ; Mohammadi, M ; Sharif University of Technology
Abstract
The effects of milling time and annealing temperature on phase formation, microstructure and magnetic properties of nickel-cobalt ferrite synthesized from oxide precursors by mechanical alloying were studied. The study of milling time effects on phase formation of milled materials showed that if milling continues up to 55 h, single phase nano-sized nickel-cobalt ferrite is obtained. Also, magnetic properties of powders versus milling time and annealing at different temperatures extensively changed, so that annealing at 1200 °C increased the magnetization saturation of the as-milled powder from 15.1 to 53.6 emu/g. X-ray powder diffraction technique (XRD) with Cu-Ka radiation was employed for...
Study of molecular conformation and activity-related properties of lipase immobilized onto core-shell structured polyacrylic acid-coated magnetic silica nanocomposite particles
, Article Langmuir ; Volume 32, Issue 13 , 2016 , Pages 3242-3252 ; 07437463 (ISSN) ; Kazemeini, M ; Singh, G ; Arpanaei, A ; Sharif University of Technology
American Chemical Society
Abstract
A facile approach for the preparation of core-shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100 000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently...