Nanostructured Materials under Ion and Microwave Radiation

Research output: ThesisDoctoral ThesisCollection of Articles

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Nanostructured Materials under Ion and Microwave Radiation. / Chalapat, Khattiya.

Aalto University, 2013. 285 p.

Research output: ThesisDoctoral ThesisCollection of Articles

Harvard

Chalapat, K 2013, 'Nanostructured Materials under Ion and Microwave Radiation', Doctor's degree, Aalto University.

APA

Chalapat, K. (2013). Nanostructured Materials under Ion and Microwave Radiation. Aalto University.

Vancouver

Chalapat K. Nanostructured Materials under Ion and Microwave Radiation. Aalto University, 2013. 285 p. (Aalto University publication series DOCTORAL DISSERTATIONS; 91).

Author

Chalapat, Khattiya. / Nanostructured Materials under Ion and Microwave Radiation. Aalto University, 2013. 285 p.

Bibtex - Download

@phdthesis{c0acf791cca041d6b582328e3990008a,
title = "Nanostructured Materials under Ion and Microwave Radiation",
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.",
keywords = "nanoscale materials, magnetic nanoparticles, carbon nanotubes, thin metal films, ferromagnetic resonance, microwave, reactive-ion etching, focused ion beam, self-organization, 3D-nanofabrication, nanoscale materials, magnetic nanoparticles, carbon nanotubes, thin metal films, ferromagnetic resonance, microwave, reactive-ion etching, focused ion beam, self-organization, 3D-nanofabrication",
author = "Khattiya Chalapat",
year = "2013",
language = "English",
isbn = "978-952-60-5188-8",
series = "Aalto University publication series DOCTORAL DISSERTATIONS",
publisher = "Aalto University",
number = "91",
school = "Aalto University",

}

RIS - Download

TY - THES

T1 - Nanostructured Materials under Ion and Microwave Radiation

AU - Chalapat, Khattiya

PY - 2013

Y1 - 2013

N2 - 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.

AB - 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.

KW - nanoscale materials

KW - magnetic nanoparticles

KW - carbon nanotubes

KW - thin metal films

KW - ferromagnetic resonance

KW - microwave

KW - reactive-ion etching

KW - focused ion beam

KW - self-organization

KW - 3D-nanofabrication

KW - nanoscale materials

KW - magnetic nanoparticles

KW - carbon nanotubes

KW - thin metal films

KW - ferromagnetic resonance

KW - microwave

KW - reactive-ion etching

KW - focused ion beam

KW - self-organization

KW - 3D-nanofabrication

M3 - Doctoral Thesis

SN - 978-952-60-5188-8

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

ID: 20664903