Nanostructured Materials under Ion and Microwave Radiation

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Paraoanu, Gheorghe-Sorin, Docent, Aalto University, Finland
dc.contributor.author Chalapat, Khattiya
dc.date.accessioned 2013-05-27T09:00:26Z
dc.date.available 2013-05-27T09:00:26Z
dc.date.issued 2013
dc.identifier.isbn 978-952-60-5189-5 (electronic)
dc.identifier.isbn 978-952-60-5188-8 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/10227
dc.description.abstract This thesis discusses how ion radiation and microwaves interact with nanoscale-structured materials. In the case of ion radiation, the experiments show that ion processing, either with low-energy ions in reactive ion etching or with higher energy ions in focused ion beams, produces inelastic strain in polycrystalline thin metallic films. This results in the bending of thin strips of metallic films, which cannot be explained by elastic models. The concept of ion-induced plastic strain implies the insertion of adatoms into grain boundaries within the metal matrix. In ion etching processes, thin strips of metallic films with different widths were released from the substrate at different times. Therefore, the rate of atomic flow into grain boundaries is different for different strips. The larger curvatures in narrower strips are the result of a faster rate of adatom insertion into the grain boundaries. With a high-energy focused ion beam, plastic strain can be created locally, allowing the fabrication of non-trivial three-dimensional structures at nanometer scales. In the case of microwave radiation, the materials studied include cobalt nanoparticles and carbon nanotubes. The magnetic resonance and absorption in cobalt nanoparticles are observed in various magnetizing fields at frequencies between 0.5 and 18 GHz, by using a wideband method. The obtained experimental results show that the energy absorption is associated with the ferromagnetic resonance of cobalt nanoparticles. The results include measurements of blocking temperature and saturation magnetization with SQUID magnetometry. The absorption spectra are analyzed theoretically by combining Kittel's theory for uniaxial spherical particles, the Landau-Lifshitz-Gilbert equation and effective medium models. At zero magnetizing field, the observed resonance occurs at higher frequencies compared to the non-interacting particle model. The shift of resonance is suggested to be caused by the clustering of particles. Transmission electron microscopic images demonstrate that indeed particles aggregate in the forms of clusters, superlattices, and chains. The absorption properties of yarns of carbon nanotubes are also presented in the thesis. en
dc.format.extent 113 + app. 172
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Aalto University en
dc.publisher Aalto-yliopisto fi
dc.relation.ispartofseries Aalto University publication series DOCTORAL DISSERTATIONS en
dc.relation.ispartofseries 91/2013
dc.relation.haspart [Publication 1]: K. Chalapat, K. Sarvala, J. Li, and G. S. Paraoanu. Wideband referenceplane invariant method for measuring electromagnetic parameters of materials. IEEE Transactions on Microwave Theory and Techniques, 57, 2257-2267 (2009).
dc.relation.haspart [Publication 2]: K. Chalapat, G. S. Paraoanu, Z. Du, J. Tervo, I. Nefedov, and S. Tretyakov. Unity absorbance layers - optimal design criteria. In Metamaterials 2010, Fourth International Congress on Advanced Electromagnetic Materials in Microwaves and Optics, 279-281 (2010).
dc.relation.haspart [Publication 3]: K. Chalapat, N. Chekurov, J. Li, and G. S. Paraoanu. Ion beam assisted self-assembly of metallic nanostructures. Nucl. Instrum. Meth. B, 272, 202-205 2012.
dc.relation.haspart [Publication 4]: K. Chalapat, N. Chekurov, H. Jiang, J. Li, B. Parviz, and G. S. Paraoanu. Self-organized origami structures via ion-induced plastic strain. Advanced Materials, 25, 91–95 (2013).
dc.relation.haspart [Publication 5]: A. Vepsäläinen, K. Chalapat, and G. S. Paraoanu. Measuring the microwave magnetic permeability of small samples using the short-circuit transmission line method. IEEE Transactions on Instrumentation and Measurement, In Press (2013).
dc.relation.haspart [Publication 6]: K. Chalapat, J. Timonen, M. Huuppola, L. Koponen, C. Johans, R. H. A. Ras, O. Ikkala, M. Oksanen, E. Seppälä, and G. S. Paraoanu. Ferromagnetic resonance of _-cobalt nanoparticle clusters. , Submitted (2013).
dc.relation.haspart [Publication 7]: J. V. I. Timonen, R. H. A. Ras, O. Ikkala, M. Oksanen, E. Seppälä, K. Chalapat, J. Li, and G. S. Paraoanu. Magnetic nanocomposites at microwave frequencies. Trends in nanophysics: theory, experiment, technology, edited by V. Barsan and A. Aldea, Engineering Materials Series, Springer-Verlag, Berlin, ISBN: 978-3-642-12069-5 pp. 257-285.
dc.subject.other Physics en
dc.title Nanostructured Materials under Ion and Microwave Radiation en
dc.type G5 Artikkeliväitöskirja fi
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department O.V. Lounasmaa -laboratorio fi
dc.contributor.department O.V. Lounasmaa Laboratory en
dc.subject.keyword nanoscale materials en
dc.subject.keyword magnetic nanoparticles en
dc.subject.keyword carbon nanotubes en
dc.subject.keyword thin metal films en
dc.subject.keyword ferromagnetic resonance en
dc.subject.keyword microwave en
dc.subject.keyword reactive-ion etching en
dc.subject.keyword focused ion beam en
dc.subject.keyword self-organization en
dc.subject.keyword 3D-nanofabrication en
dc.identifier.urn URN:ISBN:978-952-60-5189-5
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Pekola, Jukka, Prof., Aalto University, Finland
dc.opn Buks, Eyal, Assoc. Prof., Technion-Israel Institute of Technology, Israel
dc.rev Blamire, Mark, Prof., University of Cambridge, UK
dc.rev Hasar, Ugur Cem, Assoc. Prof., Ataturk University, Turkey
dc.date.defence 2013-05-24


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