Investigation of Spintronic Materials Systems: Deposition and Characterization

Citation

Oldham, Neal Curtis (2004) Investigation of Spintronic Materials Systems: Deposition and Characterization. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZAV0-8X28. https://resolver.caltech.edu/CaltechETD:etd-05272004-013645

Abstract

Continuing initiatives to deploy radical new computing schemes impel the study of new materials systems appropriate for realization of these schemes. One contemporary idea for a basis for new computing architectures is spintronics, the manipulation of electron or nuclear spin for the construction of physical quantum logic and other devices. In this work basic materials development for spintronics will be discussed. The growth and characterization of materials systems proposed as means of injecting spin-polarized electron populations into nonmagnetic semiconductors is examined. Specific materials systems analyzed include magnetite (Fe3O4), cobalt-chromium alloys, and gallia (Ga₂O₃). Deposition of these materials in thin film form with a suite of techniques including pulsed laser deposition (PLD) and electron-beam evaporation (EBE) is analyzed. Particular attention is given to the chemistry and magnetic properties of these films. Magnetic thin films of magnetite are observed upon silicon, gallium arsenide, and magnesium oxide; the epitaxy of magnetite upon indium arsenide is addressed. Additionally out-of-plane magnetization of Co-Cr alloys is demonstrated and several metallurgical issues with their deposition are discussed. Finally aspects of EBE deposition of gallium oxide for ultrathin tunnel barriers are discussed.

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