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The British Radio-Spectroscopy Group met at the University of Bristol 3-4 September, 1975, to discuss relaxation in magnetic systems. A historical review of early experiments pertaining to 'spin' of electrons and nuclei by Dr. E. ...
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The British Radio-Spectroscopy Group met at the University of Bristol 3-4 September, 1975, to discuss relaxation in magnetic systems. A historical review of early experiments pertaining to 'spin' of electrons and nuclei by Dr. E. E. Schneider of Newcastle upon Tyne. Thirteen talks were given on relaxation effects in magnetic systems investigated by nuclear magnetic and electron spin resonance techniques.
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The electron spin paramagnetic resonance of dibenzene chromium cation h a s been observed. I t s c e n t e r is a t a valhe of g = 1.98. I t shows eleven hyperfine components s e p a r a t e d by 3.5 gauss. These a r e i n t e r p...
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The electron spin paramagnetic resonance of dibenzene chromium cation h a s been observed. I t s c e n t e r is a t a valhe of g = 1.98. I t shows eleven hyperfine components s e p a r a t e d by 3.5 gauss. These a r e i n t e r p r e t e d to b e eleven of the thirteen components expected to r e s u l t f r o m the interaction of the twelve equivalent protons with the unpaired electron.
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This research explores the possibility of building a semiconductor- based quantum Hall quantum computer. The aim of this study is to develop the technology to initialize measure and manipulate the spin polarization of nuclei in se...
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This research explores the possibility of building a semiconductor- based quantum Hall quantum computer. The aim of this study is to develop the technology to initialize measure and manipulate the spin polarization of nuclei in semiconductor nanostructures which could constitute the quantum bits (qubits) and obtain electrically controlled electron mediated spin interaction between nuclear spin domains. The physical mechanism to be utilized here for the handling of nuclear spins is the hyperfine interaction which will be used to pump- and detect- nuclear polarization via Electrically Detected Electron Spin Resonance (EDESR) under microwave excitation. A hyperfine interaction / EDESR based scheme has the advantage that only nuclei in the immediate vicinity of the relevant confined electrons can via the flip-flop interaction obtain spin polarization from electrons. Thus one can obtain spatial selectivity in the polarization and measurement of spin. Indeed in gated devices where even the presence of electrons can be switched electrically one can then electrically select the ensemble of nuclei that are to obtain polarization and control their number through the choice of gate size. The study will aim to refine and improve the sensitivity of EDESR and EDNMR (Electrically Detected Nuclear Magnetic Resonance) techniques and apply them to progressively smaller structures. The project will also investigate both experimentally and theoretically the nature of electron mediated spin transfer between nuclei and the coherence and relaxation times of spins in nanostructures.
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Recently, we reported a method to determine the relative pore (accessibility) size and number distribution in selected high-volatile bituminous coal samples by diffusing nitroxide spin probes of different shapes, varying in diamet...
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Recently, we reported a method to determine the relative pore (accessibility) size and number distribution in selected high-volatile bituminous coal samples by diffusing nitroxide spin probes of different shapes, varying in diameter or length from 0.47 nm to 3.5 nm, into the swellable pores of the coal samples. The relative spin probe concentration was measured by Electron Paramagnetic Resonance (EPR) methods for each sized spin probe. EPR spectra obtained from coal samples containing spin probes gave rise to a spectrum similar to that shown in Figure 1, consisting of an intense central line due to undoped coal (curve B) and, at high gain (curve A), resolved powder EPR lines at high and low magnetic fields due to the z tensor component of the nitrogen hyperfine coupling (A/sub zz/) arising from the nitroxide spin probe dopant. The separation between the high and low field component equals 2A/sub zz/. The relative spin concentrations were determined by integrating the low field peak. The relative spin probe concentration is given in table I for probe I (reacts with amines), probe IV (reacts with acids and phenols), probe V (hydrogen bonding only to the nitroxyl group) and probe VI (hydrogen-bonding to ketone and nitroxyl groups). Notably, the ratio of pores containing acid or phenolic groups to those containing amine groups is 1/3; 6.7/1; 0.5/1; and 12/1 for Mary Lee, Black Creek, Illinois No. 5 and Illinois No. 6 respectively. (ERA citation 12:049249)
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This introductory book chapter briefly overviews some major biomedical applications of electron paramagnetic resonance (EPR) and describes basic concepts, instrumentation, and phenomena. 45 references, 15 figures, 1 table. (ERA ci...
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This introductory book chapter briefly overviews some major biomedical applications of electron paramagnetic resonance (EPR) and describes basic concepts, instrumentation, and phenomena. 45 references, 15 figures, 1 table. (ERA citation 09:044591)
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The first observation of the paramagnetic resonance of electrons at dislocations in germanium single crystals is reported. Under subband gap optical excitation, two sets of lines are detected: four lines about the <111> axes with g/sub...
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The first observation of the paramagnetic resonance of electrons at dislocations in germanium single crystals is reported. Under subband gap optical excitation, two sets of lines are detected: four lines about the <111> axes with g/sub perpendicular to/ = 0.34 and g/sub parallel/ = 1.94, and 24 lines with g/sub perpendicular to/ = 0.73 and g/sub parallel/ = 1.89 about <111> axes with the six-fold 1.2 exp 0 distortion. This represents the first measurement of the disortion angle of a dislocation dangling bond. The possibility that the distortion results from a Peierls transition along the dislocation line is discussed. (ERA citation 07:057366)
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The ESR signal of a coal sample has at least four components differing in phase angle of the magnetic modulation. The ENDOR technique was greatly improved by taking advantage of this fact, e.g., a coal sample was shown to have at ...
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The ESR signal of a coal sample has at least four components differing in phase angle of the magnetic modulation. The ENDOR technique was greatly improved by taking advantage of this fact, e.g., a coal sample was shown to have at least five different groups of free radicals. If developed, this modified ENDOR technique can be used to identify the many slightly different ingredients of a coal sample, a capability other methods do not have. (ERA citation 07:045590)
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IBM and its subcontractors achieved the major goal of this contract: the detection of individual electron spins by magnetic resonance force microscopy (MRFM). To achieve this result a number of key elements were developed, includi...
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IBM and its subcontractors achieved the major goal of this contract: the detection of individual electron spins by magnetic resonance force microscopy (MRFM). To achieve this result a number of key elements were developed, including a low temperature apparatus capable of detecting ultrasmall (attonewton) forces, specialized cantilever force sensors, methods for manipulating and detecting electron spins with random initial polarization, etc. In addition, both theoretical and experimental work has been performed to study MRFM detection of nuclear spins.
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