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dc.contributor.authorPaterson, Alexander
dc.date.accessioned2019-04-02T12:11:55Z
dc.date.available2019-04-02T12:11:55Z
dc.identifier.urihttp://hdl.handle.net/10222/75410
dc.description.abstractThe LaBGeO5 glass-ceramic composite is a transparent ferroelectric nanocomposite (TFN) material that has come under attention for its ferroelectric properties. LaBGeO5 crystals-in-glass can be formed through controlled devitrification of the glass, as well as through laser irradiation. While structural models of the glass have been proposed, they have only considered differences in the borate environment between the glass and the crystal. Understanding the structure of the LaBGeO5 glass is an important first step towards understanding the formation of the crystals-in-glass. To study the structure of the LaBGeO5 glass, we made use of a combination of nuclear magnetic resonance (NMR) spectroscopy, neutron diffraction, density functional theory (DFT) calculations, and several other techniques. These techniques provided complementary data on both local order within the glass, as well as connectivity between different local structural units. B-11 NMR spectroscopy was used to establish the presence of both trigonal and tetrahedral borate units, and to identify the trigonal borate species. B-11\{B-10\} heteronuclear NMR spectroscopy was used to probe the connectivity between the borate units. Neutron diffraction was used to provide evidence of the presence of high-coordinate germanate units, as well as evidence of changes in the lanthanum--oxygen coordination number between the glass and the crystal. La-139 NMR spectroscopy was applied to glasses for the first time in order to provide data on the La-O environment. The use of O-17 NMR spectroscopy provided data regarding the connectivity of all local structural units. The O-17 NMR data support a highly interconnected structure for the LaBGeO5 glass, and indicated that the glass network is homogeneous. DFT calculations were carried out to probe the stress environment in laser-written LaBGeO5 crystals-in-glass. Our calculations support an anisotropic stress environment with both tensile and compressive stresses being present. Our results support a model of the structure of the LaBGeO5 glass that is radically different than the crystal structure. The new structural model should inform future studies of the LaBGeO5 laser-written crystals-in-glass. Our data suggest that the nucleation mechanism in the LaBGeO5 glass is heterogeneous, and we propose future work to test this hypothesis.en_US
dc.language.isoenen_US
dc.subjectglassen_US
dc.subjectnuclear magnetic resonanceen_US
dc.subjectneutron diffractionen_US
dc.subjectdensity functional theoryen_US
dc.subjectlanthanum borogermanateen_US
dc.titleExperimental and Theoretical Investigation of Glass Ceramics: The Transparent Ferroelectric Nanocomposite LaBGeO5en_US
dc.date.defence2018-12-05
dc.contributor.departmentDepartment of Chemistryen_US
dc.contributor.degreeDoctor of Philosophyen_US
dc.contributor.external-examinerDr. Himanshu Jainen_US
dc.contributor.graduate-coordinatorDr. Peng Zhangen_US
dc.contributor.thesis-readerDr. Daniel Boyden_US
dc.contributor.thesis-readerDr. Mark Obrovacen_US
dc.contributor.thesis-readerDr. Ulrike Werner-Zwanzigeren_US
dc.contributor.thesis-supervisorDr. Josef Zwanzigeren_US
dc.contributor.ethics-approvalNot Applicableen_US
dc.contributor.manuscriptsYesen_US
dc.contributor.copyright-releaseYesen_US
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