X-ray microdiffraction is a powerful technique to study the microstructure of materials. In this thesis we built two x-ray micro diffraction setups and demonstrated their capabilities by two case studies. In our microfocusing setup, synchrotron x-rays were focused to a micron-size spot using a Fresnel zone plate. To scan the sample, we built a 3-axis translation stage with 30 nm step size over 25 mm travel range. Our x-ray diffraction imaging (topography) setup consisted of a monochromator, a channel-cut analyzer to define the diffraction angle, and a CCD camera with 0.645 mum pixels size to record the images. In our first project, we studied the microstructure of 90° ferroelectric domains and domain walls in barium titanate (BaTiO3). We discovered a ~ 1 mum surface-like layer below the surface where domain walls angle, strain, and domains orientation deviate from the bulk values. These can be explained in terms of total energy minimization and domain-domain interaction. In our second project, we used x-ray topography to measure lattice deformations in the free and bent states of a silicon micro-cantilever used in scanning probe microscopy. We found that the cantilever was twisted by 8 mdeg with respect to the base and there were small strains in the cantilever and joint area. In the bent state, we measured 0.3 m average radius of anticlastic curvature and a maximum of 2 x 10-5 strain at the edges of the cantilever. We discuss possible causes of the twist and the non-zero strains. Our setups and the tools we developed can be used to study the microstructure of other similar systems, as well.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.102506 |
| Date | January 2006 |
| Creators | Hassani, Khosrow. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physics.) |
| Rights | © Khosrow Hassani, 2006 |
| Relation | alephsysno: 002572462, proquestno: AAINR27787, Theses scanned by UMI/ProQuest. |
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