Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548215
Title: The synthesis and characterisation of pyrochlore frameworks
Author: Simon, Charles Francis
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2010
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Abstract:
Structural studies have been undertaken on a wide range of pyrochlore phases, with a focus on garnering a better understanding of the factors determining the formation and behavior of these materials. Extensive structural characterisation has been undertaken primarily using powder X-ray and powder neutron diffraction techniques to explore the subtle structural changes that occur as a result of changes in composition on the two interlocking networks that make up the pyrochlore structure. Particular attention has been paid to hydrated beta-pyrochlore materials, using high resolution TOF and constant wavelength PND to accurately determine the location and orientation of the water molecules within the structure. The location of these molecules has been shown to be directly correlated to the overall lattice dimensions of the pyrochlore framework, with the subsequent molecular orientation and internal bond angles changing to provide an optimum stabilization effect on the A-site cation. Investigation into the effects of hydration upon the superconducting beta-pyrochlore series AOs2O6.nH2O (where A = K, Rb and Cs) has also been investigated; with a correlation between the structural changes, the degree of hydration and the onset of the superconducting state being discussed. Also presented is work seeking to determine the scope and effects of ion-exchange on the A2O’ network of the pyrochlore framework, with several new phases synthesised and other known phases extensively characterized along with a discussion regarding the limits of what may be included in the pyrochlore framework.
Supervisor: Weller, Mark T. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.548215  DOI: Not available
Keywords: QD Chemistry
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