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dc.contributor.authorHay, William Johnen
dc.date.accessioned2019-02-15T14:29:19Z
dc.date.available2019-02-15T14:29:19Z
dc.date.issued1979
dc.identifier.urihttp://hdl.handle.net/1842/34643
dc.description.abstracten
dc.description.abstractThis thesis is concerned with structural studies of ferroelectric crystals, in particular the structure of CsD₂AsO₄ in its tetragonal paraelectrie phase and orthorhombic ferroelectric phase and the structures of Co₃B₇O₁₃I and Cu₃B₇7O₁₃Br in their cubic paraelectric phases. Both X-ray and neutron single-crystal diffraction techniques were used. The methods of constrained least -squares refinement and significance testing were used to determine the significance of certain structural features of interest. Details of the development of a technique for the collection of single - crystal data from an unpoled and physically unconstrained crystal in its ferroelectric phase are given. The structural studies of tetragonal CsD₂AsO₄ revealed that the D ions are disordered in double minimum potential wells. In the orthorhombic phase the D ions order onto one of their two possible sites in the tetragonal phase. The displacements of the Cs, As and O ions are related to the choice of site of the D ion on the O. . . . . O bond. The As ions move away from the O ions which the D ions have moved towards. The unusual feature of the ferroelectric transition in Cs(DₓH₁₋ₓ)₂AsO₄ suggests an inhomogeneous mixing of the hydrogen and deuterium concentration. The studies of Co₃B₇7O₁₃I and Cu₃B₇7O₁₃Br show that it is not necessary to postulate disorder to explain the crystal structures of these boracites in their cubic phase.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2019 Block 22en
dc.relation.isreferencedbyen
dc.titleStructural studies of ferroelectrics of the boracite and KH₂PO₄ typeen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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