Magnetic tunneling with CNT-based metamaterial

Multiwall carbon nanotubes (MWCNTs) fabricated by chemical vapor deposition contain magnetic nanoparticles. While increasing frequency of electromagnetic field (EMF) exposure (up to <10 kHz) of MWCNTs resulted in slight induced magnetization decrease due to skin effect of the conducting carbon, w...

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Autores principales: Kletetschka, Gunther, Inoue, Yoku, Lindauer, Jan, Hůlka, Zdeněk
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6385282/
https://www.ncbi.nlm.nih.gov/pubmed/30796318
http://dx.doi.org/10.1038/s41598-019-39325-9
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author Kletetschka, Gunther
Inoue, Yoku
Lindauer, Jan
Hůlka, Zdeněk
author_facet Kletetschka, Gunther
Inoue, Yoku
Lindauer, Jan
Hůlka, Zdeněk
author_sort Kletetschka, Gunther
collection PubMed
description Multiwall carbon nanotubes (MWCNTs) fabricated by chemical vapor deposition contain magnetic nanoparticles. While increasing frequency of electromagnetic field (EMF) exposure (up to <10 kHz) of MWCNTs resulted in slight induced magnetization decrease due to skin effect of the conducting carbon, we discovered that higher frequencies (>10 kHz) contained an exponential magnetization increase. We show that puzzling magnetization increase with decreasing magnetic field amplitude (less than 0.5 A/m for 512 kHz) is due to matching the field amplitudes of the magnetic nanoparticles inside nanotubes. This observation reveals a possibility of magnetic tunneling in MWCNTs (change of magnetic state of blocked magnetic moments). This interpretation is supported by observation of unblocking larger magnetic remanence (MR) portion from MWCNTs with progressively smaller amplitude of oscillating magnetic field.
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spelling pubmed-63852822019-02-26 Magnetic tunneling with CNT-based metamaterial Kletetschka, Gunther Inoue, Yoku Lindauer, Jan Hůlka, Zdeněk Sci Rep Article Multiwall carbon nanotubes (MWCNTs) fabricated by chemical vapor deposition contain magnetic nanoparticles. While increasing frequency of electromagnetic field (EMF) exposure (up to <10 kHz) of MWCNTs resulted in slight induced magnetization decrease due to skin effect of the conducting carbon, we discovered that higher frequencies (>10 kHz) contained an exponential magnetization increase. We show that puzzling magnetization increase with decreasing magnetic field amplitude (less than 0.5 A/m for 512 kHz) is due to matching the field amplitudes of the magnetic nanoparticles inside nanotubes. This observation reveals a possibility of magnetic tunneling in MWCNTs (change of magnetic state of blocked magnetic moments). This interpretation is supported by observation of unblocking larger magnetic remanence (MR) portion from MWCNTs with progressively smaller amplitude of oscillating magnetic field. Nature Publishing Group UK 2019-02-22 /pmc/articles/PMC6385282/ /pubmed/30796318 http://dx.doi.org/10.1038/s41598-019-39325-9 Text en © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Kletetschka, Gunther
Inoue, Yoku
Lindauer, Jan
Hůlka, Zdeněk
Magnetic tunneling with CNT-based metamaterial
title Magnetic tunneling with CNT-based metamaterial
title_full Magnetic tunneling with CNT-based metamaterial
title_fullStr Magnetic tunneling with CNT-based metamaterial
title_full_unstemmed Magnetic tunneling with CNT-based metamaterial
title_short Magnetic tunneling with CNT-based metamaterial
title_sort magnetic tunneling with cnt-based metamaterial
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6385282/
https://www.ncbi.nlm.nih.gov/pubmed/30796318
http://dx.doi.org/10.1038/s41598-019-39325-9
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