Chan, Wing Chit = (La₀.₆₇Ca₀.₃₃MnO₃/La₀.₃₀Ca₀.₇₀MnO₃/La₀.₆₇Sr₀.₃₃MnO₃/La₀.₃₀Ca₀.₇₀MnO₃)多層薄膜的電子輸運特性 / 陳榮捷. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references. / Abstract also in Chinese. / Chan, Wing Chit = (La₀.₆₇Ca₀.₃₃MnO₃/La₀.₃₀Ca₀.₇₀MnO₃/La₀.₆₇Sr₀.₃₃MnO₃/La₀.₃₀Ca₀.₇₀MnO₃) duo ceng bo mo de dian zi shu yun te xing / Chen Rongjie. / Abstract --- p.i / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xiii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Review of Magnetoresistance --- p.1 / Chapter 1.1.1 --- Giant magnetoresistance (GMR) --- p.4 / Chapter 1.1.2 --- Colossal magnetoresistance (CMR) --- p.7 / Chapter 1.2 --- Possible origins of CMR in manganites --- p.10 / Chapter 1.2.1 --- Double exchange mechanism --- p.10 / Chapter 1.2.2 --- Tolerance factor --- p.14 / Chapter 1.2.3 --- Jahn-Teller Distortion --- p.16 / Chapter 1.2.4 --- Magnetic phase diagram and charge ordering (CO) --- p.19 / Chapter 1.2.5 --- Phase separation and percolation theory --- p.23 / Chapter 1.2.6 --- Phase separation at the interfaces in thin films --- p.28 / Chapter 1.3 --- Our motivation --- p.29 / Chapter 1.4 --- Literature review of some manganite multilayer systems --- p.31 / Chapter 1.4.1 --- Ferromagnetic (FM)/antiferromagnetic (AF) multilayers --- p.31 / Chapter 1.4.2 --- Ferromagnetic (FM)/insulating oxides multilayers --- p.32 / Chapter 1.4.3 --- Ferromagnetic (FM)/ferromagnetic (FM) multilayers --- p.33 / Chapter 1.5 --- Scope of this thesis --- p.34 / References --- p.36 / Chapter Chapter 2 --- Instrumentation / Chapter 2.1 --- Thin film deposition --- p.40 / Chapter 2.1.1 --- Facing-target sputtering --- p.41 / Chapter 2.1.2 --- Vacuum system --- p.44 / Chapter 2.2 --- Characterization --- p.46 / Chapter 2.2.1 --- α-step profilometer --- p.46 / Chapter 2.2.2 --- x-ray diffraction (XRD) --- p.46 / Chapter 2.2.3 --- Resistance measurement --- p.49 / References --- p.51 / Chapter Chapter 3 --- Epitaxial growth and characterization of single layer thin films / Chapter 3.1 --- Introduction --- p.52 / Chapter 3.2 --- Fabrication of the sputtering targets --- p.52 / Chapter 3.3 --- Epitaxial growth of single layer thin films --- p.53 / Chapter 3.3.1 --- Substrate materials --- p.54 / Chapter 3.3.2 --- Deposition conditions --- p.55 / Chapter 3.3.3 --- Deposition procedures --- p.57 / Chapter 3.3 --- Characterization of single layer thin films --- p.58 / References --- p.63 / Chapter Chapter 4 --- La0 67Ca0.33MnO3/La030Ca0.70MnO3/La067Sr0.33MnO3/La0.30Ca070MnO3 multilayers / Chapter 4.1 --- Sample preparation --- p.64 / Chapter 4.2 --- Structure characterization of as-deposited samples --- p.68 / Chapter 4.3 --- Transport properties of as-deposited samples --- p.79 / Chapter 4.3.1 --- Series of samples with fixed Lao.3oCao.7oMn03 barrier layer thickness --- p.79 / Chapter 4.3.3.1 --- Samples with thin ferromagnetic layers: C20 and S20 series --- p.82 / Chapter 4.3.1.2 --- Series of samples with thick ferromagnetic layers --- p.87 / Chapter 4.3.1.3 --- Parallel resistors network --- p.96 / Chapter 4.3.2 --- Series of samples with varying Lao.3oCao.7oMn03 barrier layer thickness --- p.101 / Chapter 4.4 --- Discussion --- p.108 / References --- p.114 / Chapter Chapter 5 --- Conclusion / Chapter 5.1 --- Conclusion --- p.116 / Chapter 5.2 --- Future outlook --- p.119 / References --- p.121

Vertically aligned nanocomposite (VAN) thin films have recently stimulated significant research interest to achieve better material functionality or multifunctionalities. In VAN thin films, both phases grow epitaxially in parallel on given substrates and form a unique nano-checkerboard structure. Multiple strains, including the vertical strain which along the vertical interface and the substrate induced strain which along the film and substrate interface, exist in VAN thin films. The competition of these strains gives a promise to tune the material lattice structure and future more the nanocomposite film physical properties. Those two phases in the VAN thin films are selected based on their growth kinetics, thermodynamic stability and epitaxial growth ability on given substrates. In the present work, we investigated unique epitaxial two-phase VAN (BiFeO3)x:(Sm2O3)1-x and (La0.7Sr0.3MnO3)x:(Mn3O4)1-x thin film systems by pulsed laser deposition. These VAN thin films exhibit a highly ordered vertical columnar structure with good epitaxial quality. The strain of the two phases can be tuned by deposition parameters, e.g. deposition frequency and film composition. Their strain tunability is found to be related directly to the systematic variation of the column widths and domain structures. Their physical properties, such as dielectric loss and ferromagnetisms can be tuned systematically by this variation. The growth morphology, microstructure and material functionalities of VAN thin films can be varied by modifying the phase ratio, substrate orientation or deposition conditions. Systematic study has been done on growing (SrTiO3)0.5:(MgO)0.5 VAN thin films on SrTiO3 and MgO substrates, respectively. The variation of column width demonstrates the substrate induced strain plays another important role in the VAN thin film growth. The VAN thin films also hold promise in achieving porous thin films with ordered nanopores by thermal treatment. We selected (BiFeO3)0.5:(Sm2O3)0.5 VAN thin films as a template and get uniformly distributed bi-layered nanopores. Controllable porosity can be achieved by adjusting the microstructure of VAN (BiFeO3):(Sm2O3) thin films and the annealing parameters. In situ heating experiments within a transmission electron microscope column provide direct observations into the phases transformation, evaporation and structure reconstruction during the annealing. Systematic study in this dissertation demonstrate that the vertically aligned nanocomposite microstructure is a brand new architecture in thin films and an exciting approach that promises tunable material functionalities as well as novel nanostructures.

kein Abstract vorhanden

Thesis (Ph. D. in Electrical Engineering)--Vanderbilt University, Aug. 2003. / Title from title screen. Includes bibliographical references.

The mirrors used in high energy laser systems have at least two requirements that are uncommon in optical engineering: the reflectance of such mirrors must be very high (> 0.999), and the level of aberrations introduced by the mirrors is desired to be very low, typically λ/50 peak at 3.8 μ. The first requirement can be met by using multilayer thin film coatings, but such coatings can themselves produce aberrations in an optical system. One possible effect in multilayers is that such coatings produce an optical phase change on reflection that varies with angle of incidence and polarization of the illuminating beam. On a strongly curved mirror, such as an f/1.5 parabola used as a collimator, these effects may be appreciable for some coatings (e.g., λ/13 for a broadband all-dielectric reflector), but for an enhanced silver coating the effects are small, typically λ/400 of error that is almost entirely in the form of a small focus shift. If this same parabola is tested at its center of curvature, the coating-caused aberration due to angle of incidence effects are nearly zero (e.g., λ/50,000 for the broadband reflector that gave λ/13 when the parabola was used as a collimator). The wavefront errors due to coating nonuniformities are usually more important than angle of incidence effects. The simplest type of coating nonuniformity to analyze is a proportional error, i.e., an error where the ratios of the thicknesses of the layers are fixed but the thin film stack varies in total thickness across a surface. For a six-layer enhanced reflector for use at 3.8 μ, a 1% thickness error produces an approximate λ/100 wavefront error. At visible wavelengths, however, the aberration produced by such a coating error can be very different because of the optical interference nature of the coating. Means may be developed to estimate the performance of such an infrared reflector from measurements at visible wavelengths. If the errors produced by the coating are to be distinguished from those existing in the test due to misalignment or gravitational flexure of a large mirror, two or more wavelengths must be chosen. There are ambiguities in such a test that may be resolved by choice of an appropriate coating design or by using enough wavelengths in the visible, and both means have been studied. A technique was found where the infrared wavefront can be determined for a coating with proportional thickness errors if the coating prescription is known: interferograms of the mirror are made at three visible wavelengths, and the IR wavefront error due to the coating error is determined in a way that is insensitive to any errors caused by distortion of the substrate or even fairly large misalignments in the optical test of a mirror's figure.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed July 22, 2008). PDF text: ix, 169 p. : ill. (some col.) ; 8 Mb. UMI publication number: AAT 3299685. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed July 9, 2009; title from PDF t.p. Includes bibliographical references (p. 69-76).

Thesis (doctoral)--University of Oulu, 2008. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains xi, 108 p. : ill. (some col.) + appendix; 37 p. : ill. Includes abstract. Includes bibliographical references (p. 103-108; p. A-37).

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.