Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS

When a uniaxial magnetic field is applied to a non-magnetic dispersive medium filled with magnetic nanoparticles, they auto-assemble into thin needles parallel to the field direction, due to the strong dipolar interaction among them. We have prepared in this way magnetically oriented nanocomposites...

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Autores principales: Antonel, P.S., Negri, R.M., Leyva, A.G., Jorge, G.A.
Formato: JOUR
Materias:
Magnetic anisotropy
Magnetic viscosity
Magnetoelastomers
Relaxation
Dipolar interaction
Dispersive medium
Field directions
Local magnetic anisotropy
Logarithmic relaxation
Magnetic nanoparticles
Magnetic particle
Nanometer size
Nonmagnetics
Polydimethylsiloxane polymers
Magnetic fields
Needles
Relaxation processes
Silicones
Nanoparticles
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09214526_v407_n16_p3165_Antonel
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_09214526_v407_n16_p3165_Antonel
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spelling todo:paper_09214526_v407_n16_p3165_Antonel2023-10-03T15:45:26Z Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS Antonel, P.S. Negri, R.M. Leyva, A.G. Jorge, G.A. Magnetic anisotropy Magnetic viscosity Magnetoelastomers Relaxation Dipolar interaction Dispersive medium Field directions Local magnetic anisotropy Logarithmic relaxation Magnetic nanoparticles Magnetic particle Magnetic viscosity Magnetoelastomers Nanometer size Nonmagnetics Polydimethylsiloxane polymers Relaxation Magnetic anisotropy Magnetic fields Needles Relaxation processes Silicones Nanoparticles When a uniaxial magnetic field is applied to a non-magnetic dispersive medium filled with magnetic nanoparticles, they auto-assemble into thin needles parallel to the field direction, due to the strong dipolar interaction among them. We have prepared in this way magnetically oriented nanocomposites of nanometer-size CoFe 2O 4 particles in a polydimethylsiloxane polymer matrix, with 10% w/w of magnetic particles. We present the characteristic magnetic relaxation curves measured after the application of a magnetic field forming an angle α with respect to the needle direction. We show that the magnetic viscosity (calculated from the logarithmic relaxation curves) as a function of α presents a minimum at α=0, indicating slower relaxation processes associated with this configuration of fields. The results seems to point out that the local magnetic anisotropy of the nanoparticles is oriented along the needles, resulting in the macroscopic magnetic anisotropy observed in our measurements. © 2011 Elsevier B.V. All rights reserved. Fil:Antonel, P.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Negri, R.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Jorge, G.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09214526_v407_n16_p3165_Antonel
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Magnetic anisotropy
Magnetic viscosity
Magnetoelastomers
Relaxation
Dipolar interaction
Dispersive medium
Field directions
Local magnetic anisotropy
Logarithmic relaxation
Magnetic nanoparticles
Magnetic particle
Magnetic viscosity
Magnetoelastomers
Nanometer size
Nonmagnetics
Polydimethylsiloxane polymers
Relaxation
Magnetic anisotropy
Magnetic fields
Needles
Relaxation processes
Silicones
Nanoparticles
spellingShingle Magnetic anisotropy
Magnetic viscosity
Magnetoelastomers
Relaxation
Dipolar interaction
Dispersive medium
Field directions
Local magnetic anisotropy
Logarithmic relaxation
Magnetic nanoparticles
Magnetic particle
Magnetic viscosity
Magnetoelastomers
Nanometer size
Nonmagnetics
Polydimethylsiloxane polymers
Relaxation
Magnetic anisotropy
Magnetic fields
Needles
Relaxation processes
Silicones
Nanoparticles
Antonel, P.S.
Negri, R.M.
Leyva, A.G.
Jorge, G.A.
Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS
topic_facet Magnetic anisotropy
Magnetic viscosity
Magnetoelastomers
Relaxation
Dipolar interaction
Dispersive medium
Field directions
Local magnetic anisotropy
Logarithmic relaxation
Magnetic nanoparticles
Magnetic particle
Magnetic viscosity
Magnetoelastomers
Nanometer size
Nonmagnetics
Polydimethylsiloxane polymers
Relaxation
Magnetic anisotropy
Magnetic fields
Needles
Relaxation processes
Silicones
Nanoparticles
description When a uniaxial magnetic field is applied to a non-magnetic dispersive medium filled with magnetic nanoparticles, they auto-assemble into thin needles parallel to the field direction, due to the strong dipolar interaction among them. We have prepared in this way magnetically oriented nanocomposites of nanometer-size CoFe 2O 4 particles in a polydimethylsiloxane polymer matrix, with 10% w/w of magnetic particles. We present the characteristic magnetic relaxation curves measured after the application of a magnetic field forming an angle α with respect to the needle direction. We show that the magnetic viscosity (calculated from the logarithmic relaxation curves) as a function of α presents a minimum at α=0, indicating slower relaxation processes associated with this configuration of fields. The results seems to point out that the local magnetic anisotropy of the nanoparticles is oriented along the needles, resulting in the macroscopic magnetic anisotropy observed in our measurements. © 2011 Elsevier B.V. All rights reserved.
format JOUR
author Antonel, P.S.
Negri, R.M.
Leyva, A.G.
Jorge, G.A.
author_facet Antonel, P.S.
Negri, R.M.
Leyva, A.G.
Jorge, G.A.
author_sort Antonel, P.S.
title Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS
title_short Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS
title_full Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS
title_fullStr Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS
title_full_unstemmed Anisotropy and relaxation processes of uniaxially oriented CoFe 2O 4 nanoparticles dispersed in PDMS
title_sort anisotropy and relaxation processes of uniaxially oriented cofe 2o 4 nanoparticles dispersed in pdms
url http://hdl.handle.net/20.500.12110/paper_09214526_v407_n16_p3165_Antonel
work_keys_str_mv AT antonelps anisotropyandrelaxationprocessesofuniaxiallyorientedcofe2o4nanoparticlesdispersedinpdms
AT negrirm anisotropyandrelaxationprocessesofuniaxiallyorientedcofe2o4nanoparticlesdispersedinpdms
AT leyvaag anisotropyandrelaxationprocessesofuniaxiallyorientedcofe2o4nanoparticlesdispersedinpdms
AT jorgega anisotropyandrelaxationprocessesofuniaxiallyorientedcofe2o4nanoparticlesdispersedinpdms
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