Journal ArticleDOI
Ferromagnetic resonance and ac conductivity of a polymer composite of Fe3O4 and Fe3C nanoparticles dispersed in a graphite matrix
N. Guskos,E. A. Anagnostakis,Vlassis Likodimos,T. Bodziony,Janusz Typek,M. Maryniak,U. Narkiewicz,I. Kucharewicz,S. Waplak +8 more
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TLDR
Ferromagnetic resonance (FMR) and ac conductivity measurements have been applied to study a polymer composite containing as filler a binary mixture of magnetite (Fe3O4) and cementite nanoparticles (30-50nm) dispersed in a diamagnetic carbon matrix, which was synthesized by the carburization of nanocrystalline iron.Abstract:
Ferromagnetic resonance (FMR) and ac conductivity have been applied to study a polymer composite containing as filler a binary mixture of magnetite (Fe3O4) and cementite (Fe3C) nanoparticles (30–50nm) dispersed in a diamagnetic carbon matrix, which was synthesized by the carburization of nanocrystalline iron. Ac conductivity measurements showed thermally activated behavior involving a range of activation energies and power law frequency dependence at high frequencies similar to conducting polymer composites randomly filled with metal particles. Ferromagnetic resonance measurements revealed a relatively narrow FMR line at high temperatures indicating the presence of ferromagnetic nanoparticles, where thermal fluctuations and interparticle interactions determine the FMR temperature variation. An abrupt change of the FMR spectra was observed at T<81K (ΔT⩽1K) coinciding with a sharp anomaly resolved in the temperature derivative of the ac conductivity. This behavior is attributed to the Verwey transition of F...read more
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Hopping conductivity in polymer matrix–metal particles composites
TL;DR: In this paper, the authors investigated the temperature and frequency dependence of conductivity of polymer matrix-metal particles composites and provided evidence for the charge carriers transport mechanism via the occurred agreement of experimental results with the employed hopping models (variable range hopping model and random free energy barrier model).
Journal ArticleDOI
Electrical and magnetic properties of polyaniline/Fe3O4 nanostructures
TL;DR: In this article, electrical and magnetic properties of polyaniline (PANI) nanotubes and PANI/Fe 3 O 4 nanowires (∼140mm in diameter) with a typical size of 12.
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Effect of ferrofluid concentration on electrical and magnetic properties of the Fe3O4/PANI nanocomposites
TL;DR: In this paper, in-situ polymerization of aniline was carried out in different concentration of the ferrofluid with the aim to obtain agglomerate free nanocomposites.
Journal ArticleDOI
Poly(vinylidene fluoride)-based flexible and lightweight materials for attenuating microwave radiations.
TL;DR: This study open new avenues to design flexible and lightweight electromagnetic interference shielding materials by careful selection of functional nanoparticles in poly(vinylidene fluoride) (PVDF)-based composites.
Journal ArticleDOI
Origin of the large dispersion of magnetic properties in nanostructured oxides: FexO/Fe3O4 nanoparticles as a case study
Marta Estrader,Marta Estrader,Alberto López-Ortega,I. V. Golosovsky,Sònia Estradé,Alejandro G. Roca,German Salazar-Alvarez,Lluís López-Conesa,Dina Tobia,Elin L. Winkler,José D. Ardisson,Waldemar A. A. Macedo,A. Morphis,M. Vasilakaki,Kalliopi N. Trohidou,Arsen Gukasov,Isabelle Mirebeau,O. L. Makarova,Roberto D. Zysler,Francesca Peiró,Maria Dolors Baró,Lennart Bergström,Josep Nogués +22 more
TL;DR: A clear correlation between the magneto-structural properties in large (45 nm) and small (9 nm) FexO/Fe3O4 core/shell nanoparticles that can explain the spread of magnetic behaviors is shown.
References
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TOPICAL REVIEW: Applications of magnetic nanoparticles in biomedicine
Journal ArticleDOI
Static and dynamic magnetic properties of spherical magnetite nanoparticles
TL;DR: In this paper, a detailed study of static and dynamic magnetic behavior of Fe3O4 nanoparticles with average particle sizes ranging from 5 to 150 nm is presented, and the existence of surface spin disorder can be inferred from the decrease of saturation magnetization MS at low temperatures, as the average particle size is reduced.
Journal ArticleDOI
Universality of ac conduction in disordered solids
Jeppe C. Dyre,Thomas B. Schrøder +1 more
TL;DR: In this paper, it is argued that ac universality reflects an underlying percolation determining dc as well as ac conductivity in the extreme disorder limit, i.e., when the local randomly varying mobilities cover many orders of magnitude.
Journal ArticleDOI
The Verwey transition - a topical review
TL;DR: The story of the Verwey transition in magnetite over a period of about 90 years, from its discovery up to the present, can be subdivided into three eras as mentioned in this paper.
Book
Hopping conduction in solids
Harald Böttger,V. V. Bryksin +1 more
TL;DR: In this article, the authors present a diagram technique for strong electron-phonon coupling in the presence of a magnetic field and the Potts model for percolation problems.