% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@PHDTHESIS{Nandakumaran:908217,
author = {Nandakumaran, Nileena},
title = {{S}elf-assembly of {A}u-{F}e3{O}4 dumbbell nanoparticles},
volume = {264},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2022-02468},
isbn = {978-3-95806-666-3},
series = {Schriften des Forschungszentrums Jülich Reihe
Schlüsseltechnologien / Key Technologies},
pages = {xiv, 234},
year = {2022},
note = {Dissertation, RWTH Aachen University, 2022},
abstract = {A dumbbell nanoparticle (DBNP) system consists of an
optically active Au seed particle on which a magnetic iron
oxide nanoparticle (IONP) is heterogeneously grown. Control
and manipulation of these multi-functional hetero-structures
have applications as a dual-probe for biomedical imaging, in
catalysis, sensing, optics, photonics and electronics. This
thesis investigates the magnetic field-induced self-assembly
in diverse DBNPs, with different sizes of Au and IONPs
coated with oleic acid and oleylamine and dispersed in
toluene. The effects of DBNPs’ complex morphology
arecompared and contrasted to self-assembly studies on the
IONPs’, which are singlephase spherical counterparts.
Direct comparison simplifies the understanding of broad
parameter space, including the size of the Au seed and the
grown IONP, their size distribution, the thickness of
surfactant coating around the nanoparticle, concentration in
a dispersion, composition, magnetic structure, and strength
of the magnetic field. A multiscale experimental approach is
adopted to analyze the structure and magnetic properties to
link it to the self-assembly phenomenon. Microscopy
combinedwith local atomic structure obtained from
synchrotron x-ray pair distribution function (xPDF) is used
to reveal local crystal structure, crystallinity, size and
distortion induced at the surface. Macroscopic magnetic
measurements along with polarized neutron scattering reveal
the magnetic behavior. Small-angle x-ray and neutron
scattering (SAXS/SANS) measurements are exploited to observe
and analyze selfassembling patterns. Real-space analysis of
such patterns is achieved through reverse Monte Carlo (RMC)
simulations. Spherical IONPs reversibly form 1D chains
thatalign, straighten with magnetic field. On the other
hand, 1D and 2D chains are observed with DBNPs in an applied
magnetic field. The assemblies are classified into three
categories based on the anisotropy in the 2D scattering
pattern. Moreover, due to the unique morphology and
orientation effects, the chains formed by DBNPs within these
categories have head-to-tail or side-by-side arrangement.
Shape-induced mechanisms governed by a dimensionless
parameter are suggested to play a vital role in determining
assembly formation.},
cin = {JCNS-2 / PGI-4 / JARA-FIT},
cid = {I:(DE-Juel1)JCNS-2-20110106 / I:(DE-Juel1)PGI-4-20110106 /
$I:(DE-82)080009_20140620$},
pnm = {632 - Materials – Quantum, Complex and Functional
Materials (POF4-632) / 6G4 - Jülich Centre for Neutron
Research (JCNS) (FZJ) (POF4-6G4)},
pid = {G:(DE-HGF)POF4-632 / G:(DE-HGF)POF4-6G4},
experiment = {EXP:(DE-MLZ)KWS1-20140101 / EXP:(DE-MLZ)KWS2-20140101 /
EXP:(DE-MLZ)KWS3-20140101 / EXP:(DE-MLZ)MARIA-20140101},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
url = {https://juser.fz-juelich.de/record/908217},
}