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 81 for “"zero field"”.
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Zero Field Nmr Study on a Spin Glass: Iron-Doped 2hydrogen-Niobium Diselenide
We have used spin echoes to study the ('93)Nb NQR in 2H-NbSe(,2)Fe(,x). We measured (intensity) x (temperature), and T(,1P) (spin-lattice relaxation parameter) and T(,2) (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x = …
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Zero field NMR study on a spin glass: Iron-doped 2H-niobium diselenide
We have used spin echoes to study the 93Nb NQR in 2H-NbSe2Fex. We measured (intensity)x(temperature), and T1P (spin-lattice relaxation parameter) and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x=O, 0.25%, 1% and …
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EPR of powders, crystals, and clays of MRI contrast agents: zero field splitting and proton relaxation
… electron correlation time is dependent on the zero field splitting (ZFS) of Gd III, particularly the static ZFS component. This static ZFS of Gd III has been determined to an order of magnitude by various researchers. This work utilizes multifrequency EPR (X, Q and W Band) of dilute powders of …
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"Quantum Mechanical Analysis and Numerical Optimization of a ""zero-Field"" Spin Echo Small Angle Neutron Scattering Instrument"
The numerical simulations show that the range of spin-echo length varies from 105mum up to 10-2 mum whereas the spin-echo time from 103 ns up to 10-1ns.
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Zero-field time-of-flight characterization of minority carrier transport in heavily carbon-doped gallium arsenide and indium gallium arsenide
… GaAs and In$\sb{0.53}$G$\sb{0.47}$As using the zero-field time-of-flight (ZFTOF) technique in structures that simulate the base transport in HBTs. To extract lifetimes and diffusion coefficients from the data, an analytical solution to the minority carrier diffusion equation is found, and the …
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The Rotational Zeeman Effect in Van Der Waals Molecules
… of a superconducting solenoid is discussed. The zero field rotational spectrum of small hydrocarbon molecules with HX(X = F, Cl, CN) is analyzed and along with the Zeeman effect provides new kinds of information regarding the structure, potential surface, and charge rearrangements in weakly bound …
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Computer simulation of the structure and properties of a particulate dispersion
… investigations are limited to the cases of zero field and saturating field. An initial state of small particles is simulated by randon placements within a cubic cell with 3-D periodic boundary conditions. A secondary computation scheme is employed to expand slowly the particle lengths, …
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Characterization of a 6 MV photon beam in terms of primary and scattered dose components
… as a fraction of the total dose in a reference field at a reference depth, while μ 0 describes how the primary dose changes with depth in a medium. The scattered component is the difference between the primary and total dose. μ 0 for the beam in water was determined in four …
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Molecular Dynamics and Spin-Spin Interactions in Complex Systems: High Field and Multifrequency EPR Approach
It is shown that at high magnetic fields the Gd$\sp{3+}$ ion itself serves a sensitive probe for the microenvironment. This sensitivity allows, for example, observation of pH changes and measurement of partitioning of the lipophilic Gd$\sp{3+}$ complexes within the phospholipid membranes. …
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Moessbauer Studies of Photosynthetic Reaction Centers From Rhodopseudomonas Sphaeroides R-26
Zero field Mossbauer measurements on ('57)Fe-enriched reaction centers (RCs) differing in ubiquinone content, detergent, oxidation state, or the presence of o-phenanthroline all show a single quadrupole doublet of similar splitting (DELTA)E(,Q), center shift (delta), and temperature dependence. The …
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Visible Emitters in Hexagonal Boron Nitride as an Optically Addressable Spin Qubit Platform
… corresponds to a spin signature with small zero-field splitting (D/h < 30 MHz). Interestingly, the sign of ODMR contrast for this resonance can be positive or negative, likely arising from variability in the balance of optical rates across defects.The second manifold is a spin triplet with …
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Organic materials for second-order nonlinear optics: Approaches to optimizing and stabilizing nonlinear optical effects
… and novel single crystal films that exhibit zero-field SHG.
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Hydroxylamine-N, N-disulphonates and nitrosodisulphonates: preparations, characterizations, and magnetic and spectroscopic properties
… (S03)2N0]2H}5- groups. These species have zero-field splittings which suggest they arise from the net loss of a hydride ion from the (S03)2N0]2H}5- group. Two crystalline modifications of potassium nitrosodisulphonate and two crystalline modifications of rubidium nitrosodisulphonate were …
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Mössbauer studies of photsynthetic reaction centers from Rhodopseudomonas sphaeroides R-26
"Zero field Mossbauer measurements on 57Fe-enriched reaction centers (RCs) differing in ubiquinone content, detergent, oxidation state, or the presence of o-phenanthroline all show a single quadrupole doublet of similar splitting 6EQ, center shift 0, and temperature dependence. The results are …
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Mossbauer studies of spin coupled binuclear iron centers in proteins
… Simulations of data recorded in applied fields for the 4.2 K to 250 K temperature range have been performed with the intrinsic spin Hamiltonian $\rm {\cal H} = J{\bf S}\sb1\cdot{\bf S}\sb2 + \Sigma\sbsp{i=1}{2}\{{\bf S}\sb{i}\cdot\tilde D\sb{i}\cdot{\bf S}\sb{i} + \beta{\bf …
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Low magnetic field transitions of rhenium near the critical temperature
… shielding techniques. The ambient magnetic field at the sample was reduced to less than 10 to the -5 Gauss. For the single crystal rhenium sample isothermal magnetization curves were obtained with thermodynamic critical fields Hc between 4mG and 0.3G. The slope of Hc(T) vs. T was found to be …
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Experimental and Simulation Studies of the Processing of Nanoscale Materials: Inert Gas Condensation and Ion Irradiation Methods
… (room temperature and below), FC/ZFC (field cooled/zero field cooled) measurements clearly show the randomizing effect of irradiation. The observed phase separation behavior of Cu-Co system under irradiation fits well with the predictions of the theoretical model of Enrique and Bellon …
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The Study of Various Hydrogen-Bonded Complexes Using Pulsed, Fourier-Transform Fabry-Perot Microwave Techniques
… binding are elucidated for the complexes from zero-field spectroscopic constants. Observation of the rotational Zeeman effect for complexes involving cyclopropane gives additional electronic distribution information for the complexes and is shown to indirectly give magnetic properties for …
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Raman Scattering From the Superconductor Niobium-Diselenide
… Raman spectra at 2 K due to an applied magnetic field. The zero field results can be explained by a model (by C. A. Balseiro and L. M. Falicov) in which the optical CDW phonon modes couple to superconducting electrons, and the resulting phonon self energy is calculated using the BCS theory for …
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Electron Spin Echo and Millimeter Wave Epr Studies of Disordered Solids
… or allow for more accurate determinations of the zero-field splitting energies in a high spin system. Single crystal spectra as well as doped powder spectra of a variety of copper and iron model compounds were examined using millimeter wave EPR. The exploratory experiments, performed at 4.2 K, …
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