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1	Analysis of crystalline ammonium hexafluorophosphate using nuclear magnetic resonance force microscopy (NMRFM) and design and construction of a dynamical room-temperature NMRFM microscope Cárdenas, Rosa Elia, 1980- 31 October 2011 (has links) In this dissertation I explain the theoretical and experimental details of nuclear magnetic resonance force microscopy (NMRFM). I report the data that I have collected on ammonium hexafluorophosphate at room temperature using NMRFM. This experiment measured cantilever deflection as a function of applied magnetic field. I also report on the progress of a new dynamical room-temperature NMRFM microscope. I describe the new probe and its advantages over the previous generation probe and I show the current calibration measurements. / text NMRFM Ammonium hexafluorophosphate NMR
2	Force detected nuclear magnetic resonance on (NH₄)₂SO₄ and MgB₂ Chia, Han-Jong 07 January 2011 (has links) Nuclear magnetic resonance force microscopy (NMRFM) is a technique that combines aspects of scanning probe microscopy (SPM) and nuclear magnetic resonance (NMR) to obtain 3 dimensional nanoscale spatial resolution and perform spectroscopy. We describe the components of a helium-3 NMRFM probe and studies of ammonium sulfate ((NH₄)₂SO₄) and magnesium diboride (MgB₂). For our room temperature (NH₄)₂SO₄ studies we were able to perform a 1-D scan and perform nutation and spin echo experiments. In our 77 K MgB₂ we demonstrate a 1-D scan of a 30 micron powder sample. In addition, we describe magnetic measurements of the possible dilute semiconductors Mn[subscript x]Sc[subscript 1-x]N and Fe₀.₁Sc₀.₉N. / text NMR Nuclear magnetic resonance Magnesium diboride Dilute magnetic semiconductors NMRFM MRFM Magnetic resonance force microscopy
3	The effect of epitaxial strain and R³+ magnetism on the interfaces between polar perovskites and SrTiO₃ Monti, Mark Charles 08 June 2011 (has links) We have embarked on a systematic study of novel charge states at oxide interfaces. We have performed pulsed laser deposition (PLD) growth of epitaxial oxide thin films on single crystal oxide substrates. We studied the effects of epitaxial strain and rare-earth composition of the metal oxide thin films. We have successfully created TiO₂ terminated SrTiO₃ (STO) substrates and have grown epitaxial thin films of LaAlO₃ (LAO), LaGaO₃ (LGO), and RAlO₃ on STO using a KrF pulsed excimer laser. Current work emphasizes the importance of understanding the effect of both epitaxial strain and R³+ magnetism on the interface between RAlO₃ and STO. We have demonstrated that the interfaces between LAO/STO and LGO/STO are metallic with carrier concentrations of 1.1 x 10¹⁴ cm[superscript -2] and 4.5 x 10¹⁴ cm[superscript −2], respectively. Rare-earth aluminate films, RAlO₃, with R = Ce, Pr, Nd, Sm, Eu, Gd, and Tb, were also grown on STO. Conducting interfaces were found for R = Pr, Nd and Gd, and the results indicate that for R [does not equal] La the magnetic nature of the R³+ ion causes increased scattering with decreasing temperature that is modeled by the Kondo effect. Epitaxial strain between the polar RAlO₃ films and STO appears to play a crucial role in the transport properties of the metallic interface, where a decrease in the R³+ ion size causes an increase in sheet resistance and an increase in the onset temperatures for increased scattering. / text Oxide heterostructure LAO STO LaAlO3 SrTiO3 Perovskite Metallic interface Interfaces 2DEG Conducting interface Rare earth Rare earth magnetism Epitaxial strain PLD Pulsed laser deposition RAlO3 Rare earth aluminate Kondo NMRFM Magnetic resonance force microscopy MRFM Charge states Thin films Scattering Oxides

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