Труды сотрудников института физики

/ I. S. Lyubutin, S. G. Ovchinnikov // J. Magn. Magn. Mater. - 2012. - Vol. 324, Is. 21. - P. 3538-3541, DOI 10.1016/j.jmmm.2012.02.084. - Cited References: 16. - We acknowledge the help and discussions with Drs. A.G. Gavriliuk, V.V. Struzkin and J.F. Lin. Supports by RFBR (Grants # 09-02-00171, 10-02-00251, # 11-02-00636, # 11-02-00291, # 11-02-12089) and by the RAS Program "Strongly correlated electronic systems" are acknowledged. . - ISSN 0304-8853РУБ Materials Science, Multidisciplinary + Physics, Condensed Matter

Аннотация: The high-pressure induced phase transitions initiated by electronic transition in 3d ions from the high-spin (HS) to the low-spin (LS) state (HS-LS spin-crossover) are considered. Behavior of the system with d(6) electronic configuration is investigated in the ground state of zero temperature and critical pressure P-c. Magnetic properties of the Mott-Hubbard insulator (Mg1-xFex)O are studied in the vicinity of the quantum critical point (T=0, P-c). At the critical pressure of spin crossover P-c, the spin gap energy epsilon(S) between HS and LS states is zero. The quantum spins fluctuations HS double left right arrow LS do not require any energy, and the antiferromagnetism is destroyed in the quantum critical point by the first order transition. (C) 2012 Published by Elsevier B.V.

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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Moscow International Symposium on Magnetism(5 ; 2011 ; Aug. ; 21-25 ; Moscow)

/ V. V. Plotkin, P. G. Dyad'kov, S. G. Ovchinnikov // Russ. Geol. Geophys. - 2014. - Vol. 55, Is. 9. - P. 1138-1145, DOI 10.1016/j.rgg.2014.08.009. - Cited References: 26. - The study was supported by the Siberian Branch of the Russian Academy of Sciences (interdisciplinary integration project no. 96). . - ISSN 1068-7971. - ISSN 1878-030XРУБ Geosciences, Multidisciplinary

Аннотация: Global geomagnetic data are inverted for detecting a high-conductivity layer at depths of 1500-2000 km to test the hypothesis of a magnesiowustite phase transition in the lower mantle. We present the results of processing of both synthetic and global data-average monthly values of the geomagnetic field from 1920 to 2009. The inverted global data are consistent with the possible existence of a high-conductivity layer at great depths in the lower mantle.

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Держатели документа:
Russian Acad Sci, AA Trofimuk Inst Petr Geol & Geophys, Siberian Branch, Novosibirsk 630090, Russia
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia

Доп.точки доступа:
Dyad'kov, P. G.; Дядьков, Петр Георгиевич; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Плоткин, Валерий Викторович; Siberian Branch of the Russian Academy of Sciences [96]

/ S. G. Ovchinnikov [et al.] // J. Phys.: Conf. Ser. - 2015. - Vol. 653. - Ст. 012095, DOI 10.1088/1742-6596/653/1/012095. - Cited References:22 . - ISSN 1742-6588РУБ Physics, Applied + Physics, Multidisciplinary

Аннотация: Effect of high pressure induced spin crossover on the magnetic, electronic and structural properties of the minerals forming the Earth's low mantle is discussed. The low temperature P, T phase diagram of ferropericlase has the quantum phase transition point P = 56 GPa at T = 0 confirmed recently by the synchrotron Mossbauer spectroscopy. The LDA+GTB calculated phase diagram describes the experimental data. Its extension to the high temperature resulted earlier in prediction of the metallic properties of the Earth's mantle at the depth 1400 km h 1800 km. Estimation of the electrical conductivity based on the percolation theory is given. We discuss also the thermodynamic properties and structural anomalies resulting from the spin crossover and metal insulator transition and compare them with the experimental seismic and geomagnetic field data.

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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Ovchinnikova, T. M.; Plotkin, V. V.; Dyad'kov, P. G.; International Conference on Interaction of Intense Energy Fluxes with Matter (XXX ; 1–6 March 2015 ; Elbrus, Kabardino-Balkaria, Russia); International conference on interaction of intense energy fluxes(30 ; 2015 ; March ; 01-06)