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Hyperfine Interaction (hyperfine + interaction)
Selected AbstractsChemInform Abstract: Magnetism and Hyperfine Interactions in Gd2Ni2Mg.CHEMINFORM, Issue 43 2001Kazimierz Latka Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Photon echo in ruby doped only by 53Cr isotope ionsLASER PHYSICS LETTERS, Issue 8 2008V.V. Samartsev Abstract The signals of photon echo (PE) are investigated firstly in a ruby crystal doped only by the 53Cr isotope ions in a concentration of 0.03 , 0,05 wt%. The optical experiments were performed in backward regime at the wavelength of 693.4 nm both with a low magnetic field (200 G) and without it. Since the 53Cr isotope ions have hyperfine structure of levels the special attention was paid to the study of the stimulated photon echo and primarily to the investigation of its decay kinetics. It is established that this decay has a form which is typical to the signals of longlived PE. But in contrast to the long-lived PE the decay time in our case is less than the lifetime of the excited 2E () state. The signals of primary photon echo and stimulated photon echo at a low longitudinal magnetic field and their decay curves are investigated. We observed the beats of temporal shape of these signals with a period of several tens of nanoseconds. Theoretical analysis shows that they are due to the hyperfine interaction of valence electrons of 53Cr isotope ions with their own nuclei. The obtained decay curves allow us to estimate the phase relaxation time at the presence of a magnetic field. It proves to be equal to 98 ns. The spectrum of stimulated photon echo signal in the doped ruby exposed to a magnetic field is measured. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Electron paramagnetic resonance study of phosphorus-doped n-type homoepitaxial diamond films grown by chemical vapor depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 13 2006M. Katagiri Abstract Electron paramagnetic resonance technique has been applied to identify the microscopic origin of the n-type conductivity in phosphorus-doped {111}-homoepitaxial diamond films grown by chemical vapor deposition. The NIMS-1 center having the D2d symmetry with g|| = 1.9983, g^ = 2.0072 and the 31P hyperfine interaction of A|| = 5.77 mT, A, = 1.21 mT at 30 K is identified to be arising from the phosphorus donors based on the number of spins which matches to the number of the electrically active phosphorus atoms in the films. The wave function of the unpaired electron is localized by 12% on the phosphorus atom with a predominant p-character. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electron paramagnetic resonance and electron-nuclear double resonance of nonequivalent Yb3+ centers in stoichiometric lithium niobatePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2009Galina Malovichko Abstract Lithium niobate crystals doped with ytterbium were studied using Electron Paramagnetic Resonance (EPR) and Electron Nuclear Double Resonance (ENDOR). The tremendous narrowing of EPR lines in nearly stoichiometric samples, when compared to those in congruent samples, allowed us to distinguish nine non-equivalent centers, as well as line splitting caused by the hyperfine interaction of ytterbium electrons with the nuclear spins of two magnetic isotopes, 171Yb and 173Yb. Eight of the nine centers are described for the first time. It was found that three of the centers have axial C3 symmetry, and all others have the lowest C1 symmetry due to the presence of intrinsic defects and/or charge compensation defects in the near neighborhood of Yb3+. Characteristics of the g -tensor for all of the centers and hyperfine tensors for axial centers were determined. The ENDOR observations of Nb nuclei in the nearest neighborhood of Yb13+ gave direct evidence that the dominated axial Yb1 center has no charge compensator in its nearest surroundings (distant charge compensation mechanism). Both the EPR and ENDOR data for the main axial ytterbium center are explained by a supposition that Yb3+ ions substitute for Li+. Possible models for low-symmetry centers are discussed. The obtained numerous spectroscopic parameters can be used as cornerstones for model calculations of Yb3+ centers in lithium niobate. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] EPR of Nd3+ in congruent and nearly stoichiometric lithium niobatePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2006G. Malovichko Abstract Lithium niobate crystals doped with neodymium were studied with the help of electron paramagnetic resonance, EPR in the temperature range of 4.2,20 K. Tremendous narrowing of the EPR lines in nearly stoichiometric samples in comparison with congruent ones allowed us to distinguish four non-equivalent centers, as well as line splitting caused by hyperfine interaction of neodymium electrons with nuclear spins of both magnetic isotopes 143Nd and 145Nd. It is shown that one of the centers has axial C3 symmetry, whereas all others have lowest C1 symmetry due to presence of intrinsic defects or/and charge compensation defects in the near neighborhood of Nd3+. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nuclear field effect on the spin dynamics of electron localized on a donor in a single quantum wellPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2008C. Testelin Abstract We use photoinduced Faraday rotation (PFR) in presence of an applied magnetic field to study the spin dynamics of localized electrons. The sample is a CdTe/CdMgTe quantum well (QW) of width 80 Ĺ containing a layer of iodine donors at its center, with concentration 1011 cm,2. The spin polarization of donor-bound electrons is built via the optical polarization of donor-bound excitons, their hole spin relaxation, and their recombination. In a transverse (in-plane) magnetic field, PFR shows damped Larmor oscillations from which we deduce a 18 ns electron-spin decoherence time, and a transverse Landé factor of 1.29. In addition, for oblique optical incidence the electron-nuclei hyperfine interaction builds a nuclear spin polarization in presence of polarized electrons. This leads to the construction of an effective magnetic field, the Overhauser field, acting on the electronic spins. The Larmor frequency is then different for ,+ or ,, polarizations of the exciting light. The dependence of the phenomenon on the optical incidence allows the determination of the maximal Overhauser field, which is about 10 mT, at least two orders of magnitude weaker than for III-V semiconductors. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Local detection of Knight shift around quantum-Hall edge channels using resistively-detected NMRPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2006S. Masubuchi Abstract We develop a method for the observation of the Knight shift in nanometer-scale region in semiconductors using resistively detected nuclear magnetic resonance (RDNMR) in quantum Hall edge channels. Using a gate-induced decoupling of the hyperfine interaction between electron and nuclear spins, we obtain the RD-NMR spectra with and without the electron-nuclear spin coupling. By comparing these two NMR spectra, we obtain the values of the Knight shift for the nuclear spins polarized dynamically in the region between the relevant edge channels. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||