Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 40 for “"inelastic neutron scattering"”.
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Deep inelastic neutron scattering studies of condensed argon and neon
… over the temperature range 18.3 to 85 K by deep-inelastic-neutron scattering. The Low Resolution Medium Energy Chopper Spectrometer (LRMECS) at Argonne National Laboratory's Intense Pulsed Neutron Source (IPNS) was used to measured the neutron Compton profile over the range of wave-vector …
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Momentum density of hcp and liquid helium-4 by inelastic neutron scattering
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T16:10:35Z No. of bitstreams: 1 1983_hilleke.pdf: 5067231 bytes, checksum: d2a10e07e8841e9e47edb13560536a33 (MD5)
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Deep inelastic neutron scattering and single particle kinetic energies in condensed noble gases
… and in several condensed noble gases by deep inelastic neutron scattering. The High Resolution Medium Energy Chopper Spectrometer at the Intense Pulsed Neutron Source at Argonne National Laboratory was used to measure the dynamic structure factor at values of the wave-vector transfer between …
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Magnetic ordering and spin wave dynamics in transition metal arsenides
… structure at different temperatures using neutron powder diffraction techniques, and using inelastic neutron scattering techniques to characterize exchange interactions in these materials. We discover a new ternary metallic arsenide Cu0.82Mn1.18As which crystallizes in the hexagonal crystal …
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Deep inelastic scattering by quantum liquids
… a dominant role in the analysis of the deep inelastic neutron scattering by quantum liquids. These concepts are reviewed along with the prevalent approximations to treat final state interactions neglected in the impulse approximation.
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Raman Spectroscopy Of Glasseswith High And Broad Raman Gain In The Boson Peak Region
… on the cross section for spontaneous Raman scattering allowing to compare signal strength and spectral coverage. We also investigate the relationship between glass structure and the Boson peak (enhancement of the low-frequency vibrational density of states) and report new inelastic neutron …
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Phonon Dispersion Relations in Chrystals
Inelastic neutron scattering experiments can provide much information about the thermal motions in solids and liquids. Neutrons which have been thermalised by the moderator of a nuclear reactor have energies similar to those associated with these thermal motions. It so happens that they also have …
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Theory of High Temperature Spin Dynamics
… in the fields of nuclear magnetic resonance and inelastic neutron scattering. At the same time. those problems represent an important limit for the study of strongly interacting many-body systerns. In this thesis, we consider systems of interacting spins-both classical and quantum-and develop the …
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Geometric frustration in high spin orbit coupling magnetic materials
… applied pressure. Here, we report on our recent neutron diffraction and inelastic scattering measurements on powders and epitaxial thin films. In both samples we observe a phase transition at $T = 90$~K. In the bulk sample a weak ($\frac{\Delta a}{a} \sim 10^{-4}$), first order structural phase …
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Power-law liquid in high-temperature superconductors
… to reproduce the spin excitations observed in inelastic neutron scattering experiments. These results further our understanding of the degrees of freedom in high-$T_{c}$ superconductors and will help formulate a consistent framework incorporating the physics of the antiferromagnetic, normal, …
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Tuneable graphite intercalates for hydrogen storage
… to a principal investigation, primarily using neutron scattering and thermogravimetry, of potassium and calcium-GICs with hydrogen. Inelastic neutron scattering on hydrogenated KC24 has shown hydrogen sorption in this system to be quantitatively different from its analogues RbC24 and CsC24. A …
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Adaptive heterogeneous parallelism for semi-empirical lattice dynamics in computational materials science.
… formalism to the computational simulation of inelastic neutron scattering spectra on hybrid CPU/GPU platforms. The original ad hoc implementation as well as new patternbased and structured implementations are evaluated for relative performance and scalability. Two new structural abstractions …
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Angle-Resolved Photoemission Studies on the Many-Body Effects of High-Temperature Superconductor: Bi-2212
… states. It can be typically measured via inelastic neutron scattering (INS). However, such measurements for Bi-2212 are rare because of small scattering cross-sections and difficulties in growing sufficiently large crystals. In this work, we developed a stable photon-energy helium …
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Intrinsically Localized Lattice Vibrations in Crystalline Lattices
… and K_2/K_1 ≈0.202 respectively. Reports of Inelastic Neutron Scattering experiments have identified one-phonon breather excitations energy of 10.2 meV at elevated temperatures of 555 K. The formation of ILMs, or multi-phonon bound states, is expected to arise as a result of the anharmonic …
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Single particle kinetic energies of para-hydrogen molecules in para-hydrogen and argon solids
… and argon solids have been determined by deep inelastic neutron scattering. The Low Resolution Medium ~nergy Chopper Spectrometer at the Argonne National Laboratory's Intense Pulsed Neutron Source was used to make the measurements at momentum transfers up to 12 A-I. Peaks corresponding to …
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Supramolecular approaches to cryorelaxors for biological NMR studies
… MAS and Field Cycling NMR experiments and Inelastic Neutron Scattering spectroscopy. Crystallographically disordered methyl-group environments have been identified in a number of cases and their proton spin-lattice relaxation behaviour has been shown to be strongly dependent on the thermal …
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Frustrated Magnetism in Strongly Correlated Electron Systems
… exchanges are essential for understanding the inelastic neutron scattering experiments (INS). The presence of such higher order spin interactions has far-reaching consequences, potentially resulting in more exotic phases, such as the multipolar orders. In particular, we find propensity to …
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Orbital order in iron-based superconductors
… magnetism is unfrustrated, consistent with the inelastic neutron scattering results. The thesis is organized as follows. We will first provide the necessary background knowledge of the iron-based superconductors in Chapter 1. As a preliminary, we discuss in detail three different theoretical …
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The role of inter-plane interaction in the electronic structure of high Tc cuprates
… to the sharp magnetic resonance mode observed in inelastic neutron scattering experiments, and that this coupling is relevant to superconductivity and the pairing mechanism in the cuprates.
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Raman scattering studies of spinels CoV2O4 and MnV2O4
In this thesis, I present Raman scattering studies of the strongly correlated spinels CoV2O4 and MnV2O4. In CoV2O4, exclusive attention is given to a triply degenerate (T2g) phonon in order to determine the material's structural properties and explore coupling between the lattice and other degrees …
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