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Molecular beam epitaxy of magnetic oxynitride films : construction of a combined growth/analysis system, development of experimental tools and investigation of two oxynitride systems

University of British Columbia

The overarching theme of this thesis is the growth and characterization of thin ferromagnetic oxide films. This is a very broad project, and as a result, this thesis covers a variety of related topics. These include technical aspects, like the design and commissioning of a combined film growth and analysis system (Chapter 2), the development of an algorithm to build up surface diffraction patterns from single-reflection high-energy electron diffraction images (Chapter 3) and a chapter detailing methods to measure and correct for various non-linearities in the response of electron analyzers used in photo-electron spectroscopy (Chapter 4). An intermediate chapter (Chapter 5) deals with theoretical calculations to determine the effect of substituting pnictogens (nitrogen, phosphorous and arsenic, specifically) for oxygen in EuO. In particular, it is determined which systems are most likely to synthesize without phase separating and how the system reacts to the addition of acceptor sites from the pnictogen. This information motivates the experimental work in Chapter 6 on nitrogen-substituted EuO, which uses a novel growth technique to produce the first example of a mixed valent europium system. Both the development of a novel growth technique and the study of a new type of ferromagnetic semiconductor are important first steps in building future spintronic devices. The final chapter (Chapter 7) details attempts to grow nitrogen-substituted SrO in an attempt to induce ferromagnetic ordering in a normally non-magnetic oxide by spin polarizing the p-states. The results in this last chapter demonstrate that p-state derived magnetism is present in SrO(₁₋x)Nx.

Text

2012-10-19

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/43497

Physics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/