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11.
Yu. V. Knyazev N. B. Ivanova O. A. Bayukov N. V. Kazak L. N. Bezmaternykh A. D. Vasiliev 《Physics of the Solid State》2013,55(6):1175-1179
A concentration series of single crystals of iron-cobalt ludwigites Co3 ? x Fe x O2BO3 (x = 0.0125, 0.025, 0.050, 0.10, 1.0) has been synthesized. The structure has been studied using X-ray diffraction and Mössbauer effect. A preferred occupation of nonequivalent crystallographic positions by iron in the ludwigite structure has been revealed. It has been found that the valence of substituting iron ions is three. It has been revealed that the structure of the γ-resonance spectrum of Co2FeO2BO3 is complicated due to a composition disorder in the system. 相似文献
12.
G. M. Abramova G. A. Petrakovskiĭ O. A. Bayukov V. A. Varnek V. V. Sokolov A. F. Bovina 《Physics of the Solid State》2008,50(2):237-240
Single crystals of iron manganese sulfides Fe x Mn1 ? x S (0.25 ≤ x ≤ 0.29) are experimentally investigated using Mössbauer spectroscopy and x-ray diffraction. The Mössbauer spectra measured at 300 K exhibit a single broadened line characteristic of paramagnets. The isomer shift of this line is equal to 0.92–0.94 mm/s, which is typical of Fe2+ ions in the octahedral position. The quadrupole splitting (0.18–0.21 mm/s) suggests a distortion of the coordination polyhedron of iron ions in the Fe x Mn1 ? x S compounds. 相似文献
13.
V. G. Alpatov Yu. D. Bayukov A. V. Davydov Yu. N. Isaev G. R. Kartashov M. M. Korotkov V. V. Migachev I. N. Rozantsev M. G. Shchepkin 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(6):769-772
Experiments on the search for the effect of resonant screening on the Mössbauer absorption of 119m Sn γ rays of energy 23.8 keV emitted by a standard Mössbauer Ca119m SnO3 γ source in the resonant SnO2 absorber of natural isotopic composition are described. Intensities of tin γ rays and X-rays that passed through the absorber were measured with and without a resonant cylindrical screen (which was a black absorber for the 23.8-keV Mössbauer γ line) around the absorber and their ratios were calculated for each radiation separately. No difference beyond the experimental error was found between these ratios measured with the γ source both at rest and when oscillating with a frequency and amplitude enough to completely break the conditions for Mössbauer resonant absorption of 23.8-keV γ rays. The upper limit for the relative decrease, due to the influence of the resonant screen, in the intensities of these γ rays after their passing through the resonant absorber was 0.00030. 相似文献
14.
The combined effect of the ligand crystal field and the exchange interaction on the Cu2+ cation in CuGeO3 is examined. It is shown that, if the magnitude of the exchange interaction exceeds the splitting of the energy levels of
the
and d
xy orbitals, then an alternate filling of the d orbitals along a chain (orbital ordering) is possible. This effect creates an antiferromagnetic interaction between Cu2+ pairs in 90° exchange and a doubling of the lattice period. A Jahn-Teller pseudoeffect causes singletization of the ground
state of the antiferromagnetic chain of Cu2+ spins.
Fiz. Tverd. Tela (St. Petersburg) 40, 1686–1692 (September 1998) 相似文献
15.
Yu. D. Bayukov A. V. Davydov G. R. Kartashov M. M. Korotkov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(6):731-732
Nine sets of measurements aimed at searching for the influence of resonant environment on the half-life of the 109m Sn isomer have been performed during 14.7 months. The intensities of γ and X rays, emitted by two 261Mössbauer sources of identical design and size, were compared in these experiments. One of the sources was kept in the resonant environment of tin dioxide between measurements. No difference was found in the half-lives of 119m Sn that would be beyond the experimental errors (0.35%). 相似文献
16.
G.?A.?Petrakovski? L.?N.?Bezmaternykh D.?A.?Velikanov A.?M.?Vorotynov O.?A.?Bayukov M.?Schneider 《Physics of the Solid State》2009,51(10):2077-2083
High-quality single crystals of ludwigites Cu2 MBO5 (M = Fe3+, Ga3+) have been grown, and the magnetic, resonance, and Mössbauer studies have been performed. It is established that the Cu2FeBO5 and Cu2GaBO5 compounds are antiferromagnets with Néel temperatures of 32 and 3.4 K, respectively. A model of the magnetic structure of the compounds is proposed. It is shown that the magnetic properties of the ludwigites are substantially dependent on the degree of ion distribution over crystallographic positions. 相似文献
17.
Yu. D. Bayukov A. V. Davydov Yu. N. Isaev G. R. Kartashov M. M. Korotkov V. V. Migachev 《JETP Letters》2009,90(7):499-503
Experiments confirming the previous data on the small real width of the γ resonance of 109m Ag have been performed with a gravitational gamma-ray spectrometer. The achieved resolution is eight orders of magnitude higher than that of Mössbauer spectrometers using gamma rays from a 57Fe nuclide. The theoretically predicted broadening of the Mössbauer gamma line of 109m Ag by five orders of magnitude (due to the dipole-dipole interaction between the magnetic moments of neighboring nuclei) has not been observed. 相似文献
18.
G. A. Petrakovskii T. V. Drokina D. A. Velikanov O. A. Bayukov M. S. Molokeev A. V. Kartashev A. L. Shadrina A. A. Mitsuk 《Physics of the Solid State》2012,54(9):1813-1816
The X-ray diffraction, M?ssbauer, calorimetric, and magnetic characteristics of zirconolite GdFeTi2O7 have been measured to determine the ground magnetic state. A kink dependent on the magnetic prehistory of the sample has been revealed in the temperature dependence of the magnetic moment at T = 3 K. M?ssbauer spectroscopy has confirmed the nonequivalence of the iron ion positions in GdFeTi2O7. The experimental data obtained allow the conclusion on the formation of a spin glass state with the freezing temperature T f = 3 K in the GdFeTi2O7 compound. 相似文献
19.
T. V. Drokina G. A. Petrakovskii M. S. Molokeev D. A. Velikanov O. N. Pletnev O. A. Bayukov 《Physics of the Solid State》2013,55(10):2037-2042
Results of studying the specific features of formation of the crystal structure and distribution of iron cations over the sites in the DyFeTi2O7 compound have been presented and the comparison with the GdGaTi2O7 isostructural compound has been performed. The atomic disorder in the distribution of the Fe3+ ions over structural sites in the DyFeTi2O7 compound is confirmed by the Mössbauer spectroscopy and X-ray diffractometry. The results of magnetic measurements in the low-temperature region have revealed an inflection point in the temperature dependence of the magnetic moment and its dependence on the magnetic prehistory of the sample. The obtained experimental data suggest that there is a spin glass state with freezing point T f = 6 K in the DyFeTi2O7 compound. 相似文献
20.
V.G. Alpatov Yu.D. Bayukov A.V. Davydov Yu.N. Isaev G.R. Kartashov M.M. Korotkov V.E. Rad'ko A.A. Sadovsky V.M. Samoylov 《Hyperfine Interactions》1997,107(1-4):231-246
The temperature dependence of the 109Ag γ-ray self-absorption was investigated for the horizontal and vertical directions of emission. The source was a single-crystal
silver plate containing atoms of parent radionuclide 109Cd. Gamma-radiation of this γ-source and that of the monitoring γ-source, 57Co, were registered by a pair of Ge(Li)-detectors. As a result of cooling the source from 77 K to ~12 K a relative decrease
was observed of the intensity of the horizontally emitted γ-rays equal to 0.00064±0.00044. For the vertical direction the
corresponding intensity change turned out to be -0.00047±0.00051. Although these data, as one would see, give some evidence
for the possible effect of the gravitation on the resonant γ-ray absorption, future measurements must show if these results
aren’t a consequence of any apparatus effect. The ways for developments in this study are discussed and some hindrances are
considered.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献