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Full-Text Articles in Physics

Evaluation Of Hydrothermally Synthesized Uranium Dioxide For Novel Semiconductor Applications, Christopher M. Young Sep 2016

Evaluation Of Hydrothermally Synthesized Uranium Dioxide For Novel Semiconductor Applications, Christopher M. Young

Theses and Dissertations

Neutron radiation detection is an important part of the national strategy for nonproliferation efforts worldwide. Key to the success of these programs is detector material development which establishes the limits of efficiency, sensitivity, and power usage for a detector of practical use. This research focused upon the study of neutron detection using single crystal actinide compounds, specifically UO2, taking advantage of the successful hydrothermal synthesis of UO2 at the Air Force Research Laboratories. Initial indications are that this material may be of sufficient quality for semiconductor application.


Nmr And Nqr Study Of The Thermodynamically Stable Quasicrystals , Ananda Shastri Jan 1994

Nmr And Nqr Study Of The Thermodynamically Stable Quasicrystals , Ananda Shastri

Retrospective Theses and Dissertations

[superscript]27Al and [superscript]63,65Cu NMR measurements are reported for powder samples of stable AlCuFe and AlCuRu icosahedral quasicrystals and their crystalline approximants, and for a AlPdMn single grain quasicrystal. Furthermore, [superscript]27Al NQR spectra at 4.2 K have been observed in the AlCuFe and AlCuRu samples. From the quadrupole perturbed NMR spectra at different magnetic fields, and from the zero field NQR spectra, a wide distribution of local electric field gradient (EFG) tensor components and principal axis system orientations was found at the Al site. A model EFG calculation based on a 1/1 AlCuFe approximant was ...


Magnetic Flux Motion And Flux Pinning In Superconductors , Steven C. Sanders Jan 1992

Magnetic Flux Motion And Flux Pinning In Superconductors , Steven C. Sanders

Retrospective Theses and Dissertations

Magnetization measurements on the two high-temperature superconductors Nd[subscript]1.85Ce[subscript]0.15CuO[subscript]4-y and Ba[subscript]0.6K[subscript]0.4BiO[subscript]3 have been undertaken in order to study the reversible and irreversible magnetic behavior and compare these two different materials with other high-temperature superconductors (HTSC). While the other HTSC are known to have hole carriers and layers of CuO[subscript]2 planes in anisotropic crystal structures, Nd[subscript]1.85Ce[subscript]0.15CuO[subscript]4-y (NCCO) has electron carriers as well as hole carriers, and Ba[subscript]0.6K[subscript]0.4BiO[subscript]3 (BKBO ...


The Design, Construction And Applications Of A Novel Double-Axis Helium Atom Spectrometer , Robert L. Folkerts Jan 1992

The Design, Construction And Applications Of A Novel Double-Axis Helium Atom Spectrometer , Robert L. Folkerts

Retrospective Theses and Dissertations

A novel helium atoms spectrometer has been developed for the study of elastic and inelastic collisions with surfaces. The spectrometer is a double-axis design, providing the experimentalist with the capability of using an analyzer crystal to provide energy resolution for either elastic or inelastic experiments. The spectrometer is novel in that scattering angle at both axes may be adjusted during the experiment, allowing great flexibility in the design and execution of experiments of solid surfaces;The mechanisms and operating characteristics of the spectrometer are described. The initial tests of the spectrometer, using the well characterized LiF(001) surface, are also ...


Magnetic Properties Of High-T[Subscript C] Superconductors , Junho Gohng Jan 1992

Magnetic Properties Of High-T[Subscript C] Superconductors , Junho Gohng

Retrospective Theses and Dissertations

Magnetic properties of high-T[subscript] c superconductors have been studied in order to determine the free-energy surface, the characteristic critical fields, order parameters structure, and the grain size effect on magnetization. Studies of the thermodynamic reversibility for YBa[subscript]2Cu[subscript]3O[subscript]7-[delta] show the rounding in magnetization vs. temperature curves is a reflection of the thermodynamic fluctuations near T[subscript] c. Specific heat jump C(0)-C(H) values that have been calculated from the free-energy surfaces show good agreement with the direct calorimetric measurements;Comparative studies of the free-energy surfaces, flux creep and critical currents for ...


Electrical, Optical And Magnetic Resonance Studies Of Novel [Pi]-Conjugated Polymers , Qing-Xiao Ni Jan 1992

Electrical, Optical And Magnetic Resonance Studies Of Novel [Pi]-Conjugated Polymers , Qing-Xiao Ni

Retrospective Theses and Dissertations

Conductivity, optical properties including visible and infrared (IR) absorption and photoluminescence (PL), and magnetic resonance properties including electron spin resonance (ESR) and optically detected magnetic resonance (ODMR) have been studied in polydiethynylsilanes (PDES) and poly(2,5-dibutoxyparaphenyleneacetylene) (PDBOPA), which were recently synthesized by Dr. T. J. Barton's group at the Ames Laboratory. PDES and PDBOPA blend and PDBOPA-based electroluminescent preliminary diodes which were fabricated by the author were also explored;The undoped one-dimensional gap of PDES polymers, which have average molecular weight from ~2 x 10[superscript]5 to 1 x 10[superscript]6, is 2.0 eV in ...


Radiation Induced Flux Pinning In Yba2cu3o7-[Delta] Single Crystal , Qiang Qian Jan 1992

Radiation Induced Flux Pinning In Yba2cu3o7-[Delta] Single Crystal , Qiang Qian

Retrospective Theses and Dissertations

Radiation damage studies have been carried out to determine the changes in superconducting critical current density that result for different choices of radiation direction and magnetic field direction relative to the crystallographic axes. Single crystals of YBa[subscript]2Cu[subscript]3O[subscript]7-[delta] were irradiated with a beam of 200 MeV protons directed either parallel to the a-b plane or parallel to the c-axis. These beams created rather light damage in the form of interstitials and voids that subsequently coalesced to clusters of extra atoms in the a-b plane directed along the (100) direction. For low fluence, the main ...


Synthesis And Magnetic Properties Of Novel Ln[Subscript 2-X]Mxcuo[Subscript 4+Y] Compositions (Ln = La,Pr,Nd,Sm,Eu,Gd; M = Ca,Sr,Ba; 0<=X<=0.2; -0.5<=Y<=0.5) , Jin Hyung Cho Jan 1992

Synthesis And Magnetic Properties Of Novel Ln[Subscript 2-X]Mxcuo[Subscript 4+Y] Compositions (Ln = La,Pr,Nd,Sm,Eu,Gd; M = Ca,Sr,Ba; 0<=X<=0.2; -0.5<=Y<=0.5) , Jin Hyung Cho

Retrospective Theses and Dissertations

Ln[subscript]2CuO[subscript]4 (Ln = La, Pr, Nd, Sm, Eu, Gd) undergo structural transitions to oxygen-reduced structures Ln[subscript]2CuO[subscript]4-d with Ln = La, d = 1/3 and Ln = Pr, Nd, Sm, Eu, Gd, d = 1/2. The Nd[subscript]2CuO[subscript]4-type (T[superscript]'-phase) La[subscript]2CuO[subscript]4+d is observed after reoxygenation of oxygen-reduced La[subscript]2CuO[subscript]3.67 structure below 500°C. The magnetic properties of T/O (K[subscript]2NiF[subscript]4-type structure)-phase La[subscript]2CuO[subscript]4 systems show quite different behaviors compared with those of conventional solid state ...


Neutron Diffraction Study Of The Electronic Structure Of High-T[Subscript C] Superconductor-Related Compounds , Xun-Li Wang Jan 1992

Neutron Diffraction Study Of The Electronic Structure Of High-T[Subscript C] Superconductor-Related Compounds , Xun-Li Wang

Retrospective Theses and Dissertations

Neutron diffraction techniques have been used to study the electronic structure of La[subscript]2NiO[subscript]4 and Sr[subscript]2CuO[subscript]2Cl[subscript]2 by measuring the antiferromagnetic form factor of the single-crystal samples at 15 K. The antiferromagnetic form factor was obtained from the integrated intensities of several magnetic reflections. In both cases, the experimentally determined form factor exhibits a plateau at low Q values (up to 3 A[superscript]-1), similar to that observed for La[subscript]2CuO[subscript]4. Detailed modelling of the experimental data of these three compounds suggests that the observed plateau may be ...


Theoretical Study Of Electron-Phonon Interaction In Β-Phase Niti And Ni-Al Alloys , Guang-Lin Zhao Jan 1992

Theoretical Study Of Electron-Phonon Interaction In Β-Phase Niti And Ni-Al Alloys , Guang-Lin Zhao

Retrospective Theses and Dissertations

NiTi and Ni-Al alloys are two well known examples of materials which exhibit martensitic phase transformations, with the equiatomic NiTi alloy especially well known as the best shape memory material. At high temperature, both alloys possess the CsCl-type or B2 structure with a simple cubic (SC) lattice. They are often called [beta]-phase alloys. As temperature is lowered, the [beta]-phase NiTi and Ni-Al alloys undergo premartensitic phase transformations or premartensitic anomalies before the martensitic phase transformation. Neutron scattering measurements have found that the TA[subscript]2 (110) phonon modes in the [beta]-phases are temperature dependent and exhibit anomalous ...


Spin Dependent Recombination In Conjugated Polymers: An Optically Detected Magnetic Resonance Study , Leland Scott Swanson Jan 1991

Spin Dependent Recombination In Conjugated Polymers: An Optically Detected Magnetic Resonance Study , Leland Scott Swanson

Retrospective Theses and Dissertations

This work describes and discusses Photoluminescence (PL), and X-band Photoluminescence Detected Magnetic Resonance (PLDMR) of poly(3-alkylthiophene) (P3AT) films and solutions, poly(para-phenylenevinylene) (PPV), poly(2,5-dihexoxyparaphenylenevinylene) (PDHOPV), poly(2,5-dioctoxyparaphenylenevinylene) (PDOOPV), blends of poly(2-methoxy,5-(2[superscript]'ethylhexoxy)paraphenylenevinylene) (PMOEHOPV) with polyethylene (PE) films both unoriented and oriented, and poly(2,5-dibutoxyparaphenyleneacetylene) (PDBOPA) films. The Electroluminescence Detected Magnetic Resonance (ELDMR) and Conductivity Detected Magnetic Resonance (CDMR) narrow quenching signal in PPV is also reported and discussed.;The PLDMR of all polymers exhibit the following PL enhancing features: (i) a narrow resonance at g ≅ 2.003, (ii) a broad ...


Theoretical Study Of Hydrogen In [Alpha]-Yh[Subscript X] And On Si(111) Surface , Byeong June Min Jan 1991

Theoretical Study Of Hydrogen In [Alpha]-Yh[Subscript X] And On Si(111) Surface , Byeong June Min

Retrospective Theses and Dissertations

A first principles total energy calculation is performed to study hydrogen in an hcp metal, Y, under a Born-Oppenheimer approximation between Y and H. The equilibrium interstitial location, heat of formation, the change in the lattice constants and the bulk moduli, and the vibration frequencies of hydrogen are in excellent agreement with the experiment. However, the Born-Oppenheimer approximation is unable to make a quantitative prediction about the energy level splitting and hydrogen energy barrier between the interstitial sites. It would be out of reach to address these problems via a first principles technique. With this in mind, an empirical tight ...


Propagation Of Electromagnetic Radiation In Some Linear And Nonlinear Dielectric Stacks , Steven R. Stuve Jan 1991

Propagation Of Electromagnetic Radiation In Some Linear And Nonlinear Dielectric Stacks , Steven R. Stuve

Retrospective Theses and Dissertations

In this dissertation, we study the propagation of electromagnetic radiation in dielectric stacks, a class of structures made up of layers of dielectric which we assume to be lossless and nondispersive. We consider stacks composed of linear dielectrics with and without a nonlinearity. For computational simplicity, we often consider two specific types of dielectric stacks which we refer to as alternating and impurity stacks. Successive layers in an alternating stack alternate between two different types of dielectrics. The impurity stack is defined to be an alternating stack with one layer modified to create an "impurity" layer;We first study the ...


Magnetic Relaxation, Flux Pinning And Critical Currents In Superconductors , Karl S. Lichtenberger Jan 1991

Magnetic Relaxation, Flux Pinning And Critical Currents In Superconductors , Karl S. Lichtenberger

Retrospective Theses and Dissertations

A systematic study of the magnetic flux pinning properties in superconductors has been undertaken in an attempt to understand the differences between the flux creep behavior of classical superconductors and high-temperature superconductors (HTSC's). In HTSC's, the ratio of the effective flux pinning energy to the thermal energy, U[subscript]0/kT, is much smaller than that of conventional superconductors, often approaching unity. This results in much larger creep rates in HTSC's than in conventional superconductors. It is necessary to find suitable models that describe flux creep in both classical superconductors (i.e., Nb-Ti) and HTSC's (i ...


Hydrogen Diffusion And Microstructure In Undoped And Boron-Doped Hydrogenated Amorphous Silicon: An Ir And Sims Study , Saibal Mitra Jan 1991

Hydrogen Diffusion And Microstructure In Undoped And Boron-Doped Hydrogenated Amorphous Silicon: An Ir And Sims Study , Saibal Mitra

Retrospective Theses and Dissertations

Hydrogenated amorphous silicon (a-Si:H) prepared by rf sputtering of a polycrystalline Si target at various rf powers 50 ≤ P ≤ 550 W (0.27-2.97 W/cm[superscript]2), target to substrate distance 1 ≤ d ≤ 2[superscript]'', and varying hydrogen partial pressures. Doping was accomplished by introducing diborane (B[subscript]2H[subscript]6) in the plasma. Hydrogen diffusion was studied from the depth profiles obtained from the SIMS on multilayered a-Si:H/a-Si:(H,D)/a-Si:H samples;The properties of the samples were characterized by IR absorption, optical gap measurements and ESR. IR yielded quantitative and qualitative information total ...


Experimental Studies Of Long-Range Atomic H Motion And Desorption In Hydrogenated Amorphous Silicon And Germanium , Xiao-Lin Wu Jan 1991

Experimental Studies Of Long-Range Atomic H Motion And Desorption In Hydrogenated Amorphous Silicon And Germanium , Xiao-Lin Wu

Retrospective Theses and Dissertations

Long-range H motion and desorption in low hydrogen concentration undoped hydrogenated amorphous silicon (a-Si:H) and germanium (a-Ge:H) was studied by deuterium secondary ion mass spectrometry (SIMS) depth profiles and IR absorption of a-Si:H/a-Si:(H,D)/a-Si:H and a-Ge:H/a-Ge:(H,D)/a-Ge:H. SIMS monitors deuterium motion (assumed similar to that of H), while IR yields information on hydrogen content and bonding. The diffusion constant was found to be dispersive with time, and depended on H content C[subscript] H, diffusion length L, and microvoid content, at temperatures T ≤ 400°C for a-Si:H ...


Phenomenological Theory Of Electrodynamic Properties Of Type-Ii Superconductors , Mark W. Coffey Jan 1991

Phenomenological Theory Of Electrodynamic Properties Of Type-Ii Superconductors , Mark W. Coffey

Retrospective Theses and Dissertations

The dissertation deals with certain electrodynamic properties of type-II superconductors which are derived from phenomenological theory. For both discrete and continuous type-II superconductors, vortex dynamics are investigated and their consequences described. Many of the results of the thesis are expected to apply to high-transition temperature superconductors. The subject of dimensional crossover in a layered anisotropic superconductor and its implications for vortex structure is discussed. For discrete superconductors, specific quantitative results include the viscous drag coefficient for vortex motion parallel to the layers of a Josephson-coupled layer model, the lower critical field for parallel applied field for such a model, and ...


Theoretical Studies Of Amorphous Silicon And Hydrogenated Amorphous Silicon With Molecular Dynamics Simulations , Inhee Kwon Jan 1991

Theoretical Studies Of Amorphous Silicon And Hydrogenated Amorphous Silicon With Molecular Dynamics Simulations , Inhee Kwon

Retrospective Theses and Dissertations

Amorphous silicon (a-Si) and hydrogenated amorphous silicon (a-Si:H) have been studied with molecular dynamics simulations. The structural, vibrational, and electronic properties of these materials have been studied with computer-generated structural models and compare well with experimental observations. The stability of a-Si and a-Si:H have been studied with the aim of understanding microscopic mechanisms underlying light-induced degradation in a-Si:H (the Staebler-Wronski effect);With a view to understanding thin film growth processes, a-Si films have been generated with molecular dynamics simulations by simulating the deposition of Si-clusters on a Si(111) substrate. The Biswas-Hamann interatomic Si potential has been ...


Single Vortex Motion And Elementary Pinning Force In Snis Josephson Junctions , Qiang Li Jan 1991

Single Vortex Motion And Elementary Pinning Force In Snis Josephson Junctions , Qiang Li

Retrospective Theses and Dissertations

A new family of superconductor--normal metal--insulator--superconductor (SNIS) Josephson junctions has been developed to study the motion of a single Abrikosov vortex under the influence of a Lorentz force from an applied transport current. The location of the vortex within the junction is determined by the diffraction pattern. Methods have been developed to nucleate a single vortex by applying a transport current in one strip of the junction and systematically to push the vortex to nearly any desired location within the juction by applying currents in either of the cross-strip legs of the junction. The vortex in thin film Pb was ...


Structural, Electronic, And Magnetic Properties Of La[Subscript X]Sr[Subscript 1-X]Vo3 (0 <=X <=1.0) , Avinash Vithal Mahajan Jan 1991

Structural, Electronic, And Magnetic Properties Of La[Subscript X]Sr[Subscript 1-X]Vo3 (0 <=X <=1.0) , Avinash Vithal Mahajan

Retrospective Theses and Dissertations

We report on the properties of La[subscript] xSr[subscript] 1-xVO[subscript]3 which has a phase diagram which is similar to Sr doped La[subscript]2CuO[subscript]4 in that it too shows a composition induced insulator to metal transition with strontium doping. In addition, the insulating compositions in the vanadium based system are antiferromagnetic and the La[subscript] xSr[subscript] 1-xVO[subscript]3 system has a perovskite structure. These features are reminiscient of the properties of the high-T[subscript] c cuprate superconductors. This makes La[subscript] xSr[subscript] 1-xVO[subscript]3 a candidate for a detailed study of ...


Photoemission Study Of Ce/Ta(110) And Ce/W(110) Interfaces And The Catalytic Oxidation Effect , Chun Gu Jan 1991

Photoemission Study Of Ce/Ta(110) And Ce/W(110) Interfaces And The Catalytic Oxidation Effect , Chun Gu

Retrospective Theses and Dissertations

Photoemission spectroscopy was used to study Ce/Ta(110) and Ce/W(110) interfaces, and the catalytic oxidation effect on both surfaces. A weak Ce/Ta interface reaction is illustrated by the reduced Ta 4f surface core-level shift (SCS) upon Ce adsorption. No Ce/Ta interdiffusion was found. The Ce layer may greatly enhance the oxidation of Ta(110). Oxidation of Ce/Ta(110) at 300 K yields one monolayer (ML) of Ta suboxide (~TaO), followed by the rapid formation of Ta[subscript]2O[subscript]5. Ce/W(110) adsorption patterns were determined by low-energy electron diffraction. For [theta] ≤ 0 ...


Diamond Thin Films Grown By Microwave Plasma Assisted Chemical Vapor Deposition, Moeljanto W. Leksono Jan 1991

Diamond Thin Films Grown By Microwave Plasma Assisted Chemical Vapor Deposition, Moeljanto W. Leksono

Retrospective Theses and Dissertations

Undoped and boron doped diamond thin films have been successfully grown by microwave plasma chemical vapor deposition from CH[subscript]4, H[subscript]2, and B[subscript]2H[subscript]6. The films were characterized using x-ray diffraction techniques, Raman and infrared spectroscopies, scanning electron microscopy, secondary ion mass spectrometry, and various electrical measurements. The deposition rates of the diamond films were found to increase with the CH[subscript]4 concentration, substrate temperature, and/or pressure, and at 1.0% methane, 900°C, and 35 Torr, the value was measured to be 0.87 [mu]m/hour. The deposition rate for ...


Analysis Of Ionized Cluster Beam Thin Film Deposition , Dave Turner Jan 1991

Analysis Of Ionized Cluster Beam Thin Film Deposition , Dave Turner

Retrospective Theses and Dissertations

Ionized cluster beam (ICB) deposition has received considerable attention since its introduction in 1972 by Takagi et al. at Kyoto University because of its potential for low temperature film growth. The Kyoto University group has conducted three major experiments that indicated the presence of large clusters in varying concentrations. These three experiments form the basis for all subsequent ICB research and are supplemented by a body of indirect evidence of film formation effects that have been attributed to the presence of large clusters. Many other groups have tried to corroborate these cluster size experiments with only a few suggesting the ...


Model For The Reversible Magnetization Of High-[Kappa] Type-Ii Superconductors: Application To High-Temperature Superconductors , Zhidong Hao Jan 1991

Model For The Reversible Magnetization Of High-[Kappa] Type-Ii Superconductors: Application To High-Temperature Superconductors , Zhidong Hao

Retrospective Theses and Dissertations

This dissertation is divided into five sections, each dealing with an aspect of the response of type-II superconductors to applied magnetic fields;In Section I, a generalized variational model of a single vortex is presented, valid in the anisotropic case when the applied magnetic field H is along one of the principal axes. The effects of the anisotropy on pinning forces of individual vortices and on the vortex lattice form are discussed;In Section II, a variational model of the mixed state is proposed, which permits an analytic calculation of the free energy density F in the Ginzburg-Landau regime. A ...


Electronic And Magnetic Properties Of Strongly Correlated Systems , Tsan-Chuen Leung Jan 1991

Electronic And Magnetic Properties Of Strongly Correlated Systems , Tsan-Chuen Leung

Retrospective Theses and Dissertations

Self consistent, spin-polarized calculations are performed for Sc[subscript]2CuO[subscript]4, La[subscript]2CuO[subscript]4 with constrained d[superscript]9 configuration, and La[subscript]2NiO[subscript]4. For Sc[subscript]2CuO[subscript]4, both ferromagnetic and antiferromagnetic ground states are investigated and found to be unstable. Magnetic form factors are calculated and are discussed in view of experiments in La[subscript]2CuO[subscript]4. In the calculation for La[subscript]2CuO[subscript]4, the d[superscript]9 configuration is maintained by constraining the d[subscript]x[superscript]2-y[superscript]2 orbital to have exactly one hole. The Cu ...


Localization And Electron-Phonon Interaction In Disordered Systems , Yi Wan Jan 1990

Localization And Electron-Phonon Interaction In Disordered Systems , Yi Wan

Retrospective Theses and Dissertations

The problem of localization of electrons in the presence of electron-phonon interaction in disordered one-dimensional system is studied. In the mean-field approximation, the electron-phonon interaction results in a distorted lattice, the Peierls instability. At the same time, a gap opens at the Fermi level in the electron band. It is known that the scattering of the electrons by the disorder will destroy the lattice distortion and close the gap. However, there is disagreement on the way this happens and on the nature of the resulting electronic states. Recent progress in the experimental and theoretical studies of the one-dimensional organic polymer ...


Scanning Tunnel Microscopy Studies Of Tetrahedrally Bonded Materials , Patricia E. Allen Jan 1990

Scanning Tunnel Microscopy Studies Of Tetrahedrally Bonded Materials , Patricia E. Allen

Retrospective Theses and Dissertations

The Scanning Tunnel Microscope (STM) is a surface analysis tool that has been used to study the geometric and electronic properties of metals, semimetals and semiconductors. Evaporated gold deposited on glass was examined as a preliminary test of the McAllister/RHK STM. Calibration of the STM system was accomplished by imaging annealed pyrolytic graphite (APG), but with surprising results. The peak spacing agreed with the accepted value for STM graphite images of 2.46 A, but the shape of the peaks were often distorted. These distortions can be understood in view of the theoretical work of Kobayashi and Tsukada on ...


Inverse-Photoemission Spectroscopy Of Fexo, Ag , Bongsoo Kim Jan 1990

Inverse-Photoemission Spectroscopy Of Fexo, Ag , Bongsoo Kim

Retrospective Theses and Dissertations

I measured the inverse-photoemission spectra (IPES) of iron oxides grown on an Fe substrate, and calculated the band structure of paramagnetic FeO to analyze the IPES. The band calculation showed some overlap between Fe3 d states and O2 p states in the region of occupied states, and s,p-like states of Fe in the unoccupied region. Isochromatic IPES showed structures at ~2.5 eV and ~7.5 eV above the Fermi energy. I estimate the full band gap of FeO as 2.5 eV from the IPES data;Angle-resolved inverse-photoemission spectra (ARIPES) have been measured on single-crystal Ag. The results ...


Optical Properties And Electronic Structures Of D- And F-Electron Metals And Alloys, Ag-In, Ni-Cu, Auga2, Ptga2, [Beta]'-Nial, [Beta]'-Coal, Cesn3, And Lasn3 , Kwang Joo Kim Jan 1990

Optical Properties And Electronic Structures Of D- And F-Electron Metals And Alloys, Ag-In, Ni-Cu, Auga2, Ptga2, [Beta]'-Nial, [Beta]'-Coal, Cesn3, And Lasn3 , Kwang Joo Kim

Retrospective Theses and Dissertations

Optical properties and electronic structures of disordered Ag[subscript]1-xIn[subscript]x (x = 0.0, 0.04, 0.08, 0.12) and Ni[subscript]1-xCu[subscript]x(x = 0.0, 0.1, 0.3, 0.4) alloys and ordered AuGa[subscript]2, PtGa[subscript]2, [beta][superscript]'-NiAl, [beta][superscript]'-CoAl, CeSn[subscript]3, and LaSn[subscript]3 have been studied. The complex dielectric functions have been determined for Ag[subscript]1-xIn[subscript]x,Ni[subscript]1-xCu[subscript]x,AuGa[subscript]2, and PtGa[subscript]2 in the 1.2-5.5 eV region and for CeSn[subscript]3 and LaSn ...


High Resolution Electron Energy Loss Studies Of O2, H, N, No, And N2o Adsorption On Germanium Surfaces , Anthony G. Entringer Jan 1990

High Resolution Electron Energy Loss Studies Of O2, H, N, No, And N2o Adsorption On Germanium Surfaces , Anthony G. Entringer

Retrospective Theses and Dissertations

The first high resolution electron energy loss spectroscopy (HREELS) studies of the oxidation and nitridation of germanium surfaces are reported. Both single crystal Ge(111) and disordered surfaces were studied. Surfaces were exposed to H, O[subscript]2, NO, N[subscript]2O, and N, after cleaning in ultra-high vacuum. The Ge surfaces were found to be non-reactive to molecular hydrogen (H[subscript]2) at room temperature. Exposure to atomic hydrogen (H) resulted hydrogen adsorption as demonstrated by the presence of Ge-H vibrational modes. The HREEL spectrum of the native oxide of Ge characteristic of [nu]-GeO[subscript]2 was obtained ...