scholarly journals On the Dielectric and Magnetic Properties of Nanocomposites

2007 ◽  
Vol 2007 ◽  
pp. 1-11 ◽  
Author(s):  
B. Hallouet ◽  
B. Wetzel ◽  
R. Pelster
Keyword(s):  
Molecular Dynamics ◽  
Magnetic Properties ◽  
Polymer Matrix ◽  
Magnetite Nanoparticles ◽  
Particle Concentration ◽  
Spectral Representation ◽  
Low Frequency ◽  
Magnetic Data ◽  
Model Free ◽  
Effective Medium Models

We investigate nanocomposites, that is, dispersions of magnetite nanoparticles in an epoxy resin, by means of broadband dielectric and magnetic spectroscopy. The molecular dynamics of the polymer matrix is altered by the nanoparticles. Due to the formation of agglomerates neither permittivity nor permeability can be described with known effective medium models. We use the spectral representation (Bergman theorem) to show that a model-free evaluation of the low-frequency permeability of the nanoparticles can be achieved by combining dielectric and magnetic data. In addition, the ferromagnetic resonance is studied experimentally. It occurs near 3 GHz and is independent of the particle concentration.

DC and AC Measurements of Magnetite Nanoparticulates and Implications for Nonlinear Response

2008 ◽  
Vol 1138 ◽  
Author(s):  
Silvia Liong ◽  
Ricky Lamar Moore
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Polymer Composites ◽  
Magnetic Measurements ◽  
Bulk Material ◽  
Low Frequency ◽  
Anisotropy Field ◽  
Coaxial Line ◽  
Magnetic Data ◽  
Order Of Magnitude

AbstractThis paper discusses preparation, characterization and measurement of linear DC and AC magnetic properties of magnetite (Fe3O4) nanoparticles (size ranges of 7-50 nm and 5 microns) and polymer composites of those particulates. Selected data and analysis are taken from the PhD thesis of Liong [1]. The goal of this research is to obtain magnetic data, specifically magnetization, anisotropy and coercivity as functions of particle size. These will be used as inputs to non linear magnetic simulations and in planning for future nonlinear magnetic measurements. Magnetite nanoparticles were synthesized by chemical coprecipitation, a method that allowed for the production of samples in gram quantities. Vibrating sample magnetometry was used to measure the room-temperature DC magnetization and coercivity of the particulates. Coaxial line impedance measurements were used to measure low frequency and dispersive AC permeability of Fe3O4–polymer composites from 1 Megahertz to 10 Gigahertz. AC data are applied to infer particulate magnetic susceptibility and anisotropy field change with particle size. Particle size was calculated from XTD data and supported by TEM images.Measured DC saturation magnetization and coercivity decreased with particle dimension while anisotropy was calculated to increase. Magnetization data are consistent with models that calculate nanoparticle magnetization as a volumetric average of a spherical bulk material core and a passive outer shell. The shell thickness was calculated at 0.84 nm, very near one lattice constant of bulk Fe3O4, 0.8394 nm. Composites containing particulate volume fractions less than 20% were fabricated. Effective media theory was applied to measured AC composite permeability to extract particle magnetic properties and thereby anisotropy field, which increased by an order of magnitude from the bulk. Permeability decreased with particulate size.

Thermal, mechanical and magnetic properties of functionalized magnetite/vinyl ester nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (94) ◽  
pp. 91584-91593 ◽  
Author(s):  
Dawei Jiang ◽  
Yinghong Huan ◽  
Caiying Sun ◽  
Chunping Hu ◽  
Jiang Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Properties ◽  
Polymer Matrix ◽  
Magnetite Nanoparticles ◽  
Vinyl Ester

Thiol functionalized magnetite nanoparticles increased the mechanical properties of the polymer matrix while introducing magnetic properties.

Magnetic properties of bacterial magnetosomes and chemosynthesized magnetite nanoparticles

2008 ◽  
Vol 44 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M. Timko ◽  
A. Dżarová ◽  
V. Závišová ◽  
M. Koneracká ◽  
A. Šprincová ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetite Nanoparticles

Complexes of copper(II) and nickel(II) with a Schiff base bonded to a polymeric support

1983 ◽  
Vol 48 (7) ◽  
pp. 2021-2027 ◽  
Author(s):  
Eliška Kálalová ◽  
Olga Populová ◽  
Štěpánka Štokrová ◽  
Pavel Stopka
Keyword(s):  
Magnetic Properties ◽  
Schiff Base ◽  
Coordination Sphere ◽  
Polymer Matrix ◽  
Glycidyl Methacrylate ◽  
Epr Spectra ◽  
Polymeric Support ◽  
Tetrahedral Configuration ◽  
Paramagnetic Complexes

Copper(II) and nickel(II) ions were bonded in complexes of salicylideneimine type on a glycidyl methacrylate-ethylenedimethacrylate copolymer. The geometry of the complexes on the polymer was studied by measuring their magnetic properties, EPR spectra, and ultraviolet-visible spectra.Only paramagnetic complexes possessing a pseudo-tetrahedral configuration were found. The effect of the polymer matrix and of the immobility of the bonded Schiff base on the distortion of the coordination sphere of the central ion is discussed.

scholarly journals Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Low Frequency ◽  
Solid State Reaction Method ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Frequency Regime ◽  
Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

Molecular Dynamics Simulation of a Pullout Test on a Carbon Nanotube in a Polymer Matrix

2014 ◽  
Vol 1700 ◽  
pp. 61-66
Author(s):  
Guttormur Arnar Ingvason ◽  
Virginie Rollin
Keyword(s):  
Molecular Dynamics ◽  
Polymer Matrix ◽  
Large Scale ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Atomistic Simulations ◽  
Polymer Molecules ◽  
Molecular Potential ◽  
Pull Out ◽  
Walled Carbon Nanotubes

ABSTRACTAdding single walled carbon nanotubes (SWCNT) to a polymer matrix can improve the delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics (MD) simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential. This potential includes non-bonded interactions, as well as bonds, angles and dihedrals to create a MD model for a SWCNT and EPON 862/DETDA (Diethyltoluenediamine) polymer matrix. Two simulations were performed in order to test the implementation of the COMPASS parameters. The first one was a tensile test on a SWCNT, leading to a Young’s modulus of 1.4 TPa at 300K. The second one was a pull-out test of a SWCNT from an originally uncured EPON 862/DETDA matrix.

Synthesis and Characterization of Particle-reinforced Ni/Al2O3 Nanocomposites

2002 ◽  
Vol 17 (6) ◽  
pp. 1412-1418 ◽  
Author(s):  
I. Shao ◽  
P. M. Vereecken ◽  
C. L. Chien ◽  
P. C. Searson ◽  
R. C. Cammarata
Keyword(s):  
Magnetic Properties ◽  
Rotation Rate ◽  
Particle Concentration ◽  
Volume Fraction ◽  
Particle Dispersion ◽  
Nanocomposite Films ◽  
Synthesis And Characterization ◽  
Electrode Rotation ◽  
Deposition Current Density

Nanocomposite Ni/Al2O3 films were electrodeposited from a suspension of Al2O3 nanoparticles in aqueous nickel sulfamate solution. The volume fraction of particles incorporated increased with electrode rotation rate and decreased with deposition current density. The composition, microstructure, hardness, and magnetic properties of these nanocomposite films were characterized. The mechanical strengthening due to particle dispersion in the films was interpreted by considering an Orowan dislocation bowing mechanism. The coercivity of the films increased with increasing particle concentration in the film. The saturation magnetization showed a weak dependence on particle concentration.

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