Труды сотрудников института физики

/ I. S. Edelman [et al.] // Phys. Chem. Glasses - Eur. J. Glass Sci. Technol. Part B. - 2012. - Vol. 53, Is. 2. - P. 37-44. - Cited References: 22 . - ISSN 1753-3562РУБ Chemistry, Physical + Materials Science, Ceramics

Аннотация: A comparative multitechnique study (including transmission electron microscopy, synchrotron radiation, static magnetisation, magnetic circular dichroism and electron magnetic resonance) has been carried out of nanoparticle-containing borate glasses of two different types: (i) with iron and manganese oxide additives and (ii) with iron and rare earth oxide additives. Due to the presence of magnetic nanoparticles, these glasses have a nonlinear magnetic field dependence of magnetization with hysteresis and saturation while remaining transparent in the visible and near-infrared spectral ranges. The nature of the nanoparticles has been identified as manganese ferrite for type (i) glasses and maghemite for type (ii) glasses. The synchrotron radiation studies as well as the computer-assisted electron magnetic resonance provide an insight into the morphological characteristics of the magnetic nanoparticles in the glass.

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Доп.точки доступа:
Edelman, I. S.; Эдельман, Ирина Самсоновна; Ivanova, O.; Ivantsov, R. D.; Иванцов, Руслан Дмитриевич; Petrakovskaja, E. A.; Петраковская, Элеонора Анатольевна; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Zabluda, V. N.; Заблуда, Владимир Николаевич; Hennet, L.; Thiaudiere, D.; Saboungi, M. L.; Zubavichus, Y.; Stepanov, S.; Zaikovskii, V. I.; Artemenko, A.; Kliava, J.; International Conference on the Chemistry of Glasses and Glass-Forming Melts (2011 ; Sept. ; Oxford, England)

/ T. A. Val'kova, V. V. Val'kov // Bull. Russ. Acad. Sci.: Phys. - 2012. - Vol. 76, Is. 7. - P. 768-770, DOI 10.3103/S1062873812070374. - Cited References: 7. - This work was supported by the Quantum Physics of Condensed Matter Program for Basic Research of the Presidium of the Russian Academy of Sciences; and by the federal target program Scientists and Science Teachers of an Innovative Russia, 2009–2013. . - ISSN 1062-8738
Аннотация: Using the diagram technique for spin operators, the exact representations for quantum magnets are obtained that express the Green's functions via the components of mass operator ∑αβ, end factors L and Q, and the Larkin-and Dyson-irreducible part T- irr.The elementary excitation spectrum and mean magnetization are calculated accurate to the first-order contributions on the parameter r0 -3 by the self-consistent field method.

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Доп.точки доступа:
Val'kov, V. V.; Вальков, Валерий Владимирович; International Interdisciplinary Symposium “Ordering in Minerals and Alloys” (14th ; 8 -13 Sept. 2011 ; Rostov-on-Don)

/ E. N. Kablov [et al.] // Russ. Metall. (Metally). - 2014. - Vol. 2014, Is. 1. - P. 55-59, DOI 10.1134/S0036029514010078. - Cited References: 15 . - ISSN 0036-0295. - ISSN 1555-6255
Аннотация: The effect of copper on the properties of magnets (Pr0.52Dy0.48)13(Fe65Co0.35)80.3 - xCuxB6.7 (x = 0-10) has been studied. Alloying with copper is shown to decrease the sintering temperature and to increase the content of the principal (Pr,Dy)2(Fe,Co)14B magnetic phase. For compositions with x = 1.3-3.3, copper is found to affect the value and sign of the temperature induction coefficient (TIC). It is shown that the effect of copper on the TIC is determined by the substitution of copper ions for iron ions in lattice sites, which are coupled via an antiferromagnetic exchange interaction. © 2014 Pleiades Publishing, Ltd.

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Держатели документа:
All-Russia Scientific Research Institute of Aviation Materials, ul. Radio 17, Moscow, 105005, Russian Federation
Kirenskii Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50, bld. 38, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Kablov, E. N.; Piskorskii, V. P.; Valeev, R. A.; Volkov, N. V.; Волков, Никита Валентинович; Davydova, E. A.; Shaikhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Balaev, D. A.; Балаев, Дмитрий Александрович; Semenov, S. V.; Семёнов, Сергей Васильевич

/ V. V. Val'kov, M. S. Shustin // JETP Letters. - 2014. - Vol. 100, Is. 7. - P. 455-462, DOI 10.1134/S0021364014190138. - Cited References: 28. - This work was supported by the Russian Foundation for Basic Research, project nos. 12-02-31130, 13-02-00523, and 13-02-98013. . - ISSN 0021-3640. - ISSN 1090-6487РУБ Physics, Multidisciplinary

Аннотация: TThe excitation spectrum of a catena-[FeII(ClO4)2{FeIII(bpca)2}]ClO4 anisotropic 1D magnet with alternating high-spin and low-spin iron ions has been calculated with the use of the diagrammatic technique for Hubbard operators. This has allowed establishing conformity with the Ising model, for which the magnetic susceptibility has been calculated by the transfer-matrix method. The introduction of a statistical ensemble taking into account the presence of chains with different lengths and iron ions with different spins has allowed describing the modification of the magnetic susceptibility under optical irradiation.

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Держатели документа:
Russian Acad Sci, Siberian Branch, Kirensky Inst Phys, Krasnoyarsk 660036, Russia
Siberian Fed Univ, Krasnoyarsk 660041, Russia

Доп.точки доступа:
Shustin, M. S.; Шустин, Максим Сергеевич; Вальков, Валерий Владимирович; Russian Foundation for Basic Research [12-02-31130, 13-02-00523, 13-02-98013]

/ V. V. Val’kov, M. S. Shustin // Bull. Russ. Acad. Sci. Phys. - 2015. - Vol. 79, Is. 6. - P. 734-736, DOI 10.3103/S1062873815060337. - Cited References: 4. - The work was supported by the Russian Foundation for Basic Research, project nos. 13-02-00523, 13-02-98013, and 14-02-31280). . - ISSN 1062-8738
Аннотация: The exitation spectrum of a ferrimagnetic Heisenberg chain with four sublattices and twisting mutually ortoghonal easy planes is calculated using a diagram technique of atomic representation. It is shown that at low temperatures, the exitation spectrum of elementary excitations of the system is similar to the spectrum of a magnet with an effective easy-axis type anisotropy directed along the line of easy plane intersection. © 2015, Allerton Press, Inc.

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Держатели документа:
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Shustin, M. S.; Вальков, Валерий Владимирович

/ S. V. Komogortsev [et al.] // J. Magn. Magn. Mater. - 2016. - Vol. 401. - P. 236-241, DOI 10.1016/j.jmmm.2015.10.041. - Cited References: 55. - The work has been partially supported by RFBR Grants 15-08-06673, 14-03-00411, 14-03-00129, 15-42-0417115 and it is partly performed in Siberian Federal University within the state contract of the Russian Federation Ministry of Education and Science for 2014-2016 (project number 1792) . - ISSN 0304-8853
   Перевод заглавия: Влияния обменного взаимодействия на магнитные свойства наноструктурированных частиц CoPtРУБ Materials Science, Multidisciplinary + Physics, Condensed Matter

Аннотация: Various manifestations of the exchange interaction effects in magnetization curves of the CoPt nanostructured particles are demonstrated and discussed. The inter-grain exchange constant A in the sponge-like agglomerates of crystallites is estimated as A=(7±1) pJ/m from the approach magnetization to saturation curves that is in good agreement with A=(6.6±0.5) pJ/m obtained from Bloch T 3/2 law. The fractal dimensionality of the exchange coupled crystallite system in the porous media of the disordered CoPt alloy d=(2.60±0.18) was estimated from the approach magnetization to saturation curve. Coercive force decreases with temperature as Hc~T 3/2 which is assumed to be a consequence of the magnetic anisotropy energy reduction due to the thermal spin wave excitations in the investigated CoPt particles. © 2015 Elsevier B.V. All rightsreserved.
Демонстрируются и обсуждаются различные проявления эффектов обменного взаимодействия в кривых намагниченности наноструктуированных частиц CoPt. Межзеренная обменная константа А в агломератах губчатой структуры кристаллитов оценивается как /A/=(7±1) pJ/m из кривых приближения намагниченности к насыщению, это значение находится в хорошем согласии с /A/=(6.6±0.5) pJ/m, полученным из закона /T/. /2 Блоха. Размерность фрактала обменно-соединенных кристаллических систем в пористой среды неупорядоченного сплава CoPt /d/=(2.60±0.18) оценивалась из кривых приближения намагниченности к насыщению. Коэрцитивная сила уменьшается с температурой по закону /H_c /~/T/. /2 , который, как предполагается, есть следствие уменьшения энергии магнитной анизотропии из-за теплового возбуждения спиновых волн в изучаемых частицах CoPt.

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Держатели документа:
Kirensky Institute of Physics, SB RAS, Krasnoyarsk, Russian Federation
Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk, Russian Federation
Novosibirsk State University, Novosibirsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Komogortsev, S. V.; Комогорцев, Сергей Викторович; Iskhakov, R. S.; Исхаков, Рауф Садыкович; Zimin, A. A.; Зимин, А. А.; Filatov, E. Y.; Korenev, S. V.; Shubin, Yu. V.; Chizhik, N. A.; Yurkin, G. Yu.; Юркин, Глеб Юрьевич; Eremin, E. V.; Еремин, Евгений Владимирович

/ V. V. Val'kov, M. S. Shustin // J. Exp. Theor. Phys. - 2015. - Vol. 121, Is. 5. - P. 860-877, DOI 10.1134/S1063776115110175. - Cited References:46. - This work was supported by the Russian Foundation for Basic Research, project nos. 13-02-00523, 14-02-31237, and 15-42-04372 . - ISSN 1063-7761. - ISSN 1090-6509РУБ Physics, Multidisciplinary

Аннотация: The dispersion equation of a strongly anisotropic one-dimensional magnet catena-[FeII(ClO4)2{FeIII(bpca)2}]ClO4 containing alternating high-spin (HS) (S = 2) and low-spin (LS) (S = 1/2) iron ions is obtained by the diagram technique for Hubbard operators. The analysis of this equation yields six branches in the excitation spectrum of this magnet. It is important that the crystal field for ions with spin S = 2 is described by the Hamiltonian of single-ion easy-plane anisotropy, whose orientation is changed by 90° when passing from one HS iron ion to another. The U(N) transformation technique in the atomic representation is applied to diagonalize a single-ion Hamiltonian with a large number of levels. It is shown that the modulation of the orientation of easy magnetization planes leads to a model of a ferrimagnet with easy-axis anisotropy and to the formation of energy spectrum with a large gap. For HS iron ions, a decrease in the mean value of the spin projection due to quantum fluctuations is calculated. The analysis of the specific features of the spectrum of elementary excitations allows one to establish a correspondence to a generalized Ising model for which the magnetic susceptibility is calculated in a wide range of temperatures by the transfer-matrix method. The introduction of a statistical ensemble that takes into account the presence of chains of different lengths and the presence of iron ions with different spins allows one to describe the experimentally observed modification of the magnetic susceptibility of the magnet under optical irradiation.

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Держатели документа:
Russian Acad Sci, Siberian Branch, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.

Доп.точки доступа:
Shustin, M. S.; Шустин, Максим Сергеевич; Вальков, Валерий Владимирович; Russian Foundation for Basic Research [13-02-00523, 14-02-31237, 15-42-04372]

/ K. A. Shaykhutdinov [et al.] // J. Appl. Phys. - 2011. - Vol. 109, Is. 5. - Ст. 53711, DOI 10.1063/1.3559303. - Cited References: 20. - This study was partially supported by the Russian Foundation for Basic Research, Project No. 08-02-00259a and the Lavrentyev Competition of the Young Scientists' Projects of the Siberian Branch of the Russian Academy of Sciences, Project No. 12. . - ISSN 0021-8979РУБ Physics, Applied

Аннотация: The behavior of temperature dependences of electrical resistance and magnetoresistance of polycrystalline substituted lanthanum manganite (La0.5Eu0.5)(0.7)Pb0.3MnO3 at low temperatures was thoroughly studied. A broad hysteresis was found in the field dependences of electrical resistance in the low-temperature region. Above 40 K, no hysteresis feature was observed. The temperature T = 40 K corresponds to the temperature of minimum electrical resistance and the temperature T-N to the antiferromagnet-paramagnet phase transition of the material of the intergrain boundaries. In this work we propose a model which explains the observed features of the rho(T) and rho(H) curves at temperatures below T-N by the formation of a network of ferromagnet-antiferromagnet-ferromagnet tunnel contacts. (C) 2011 American Institute of Physics. [doi:10.1063/1.3559303]

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Держатели документа:
[Shaykhutdinov, K. A.
Popkov, S. I.
Semenov, S. V.
Balaev, D. A.
Dubrovskiy, A. A.
Sablina, K. A.
Sapronova, N. V.
Volkov, N. V.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Shaykhutdinov, K. A.
Balaev, D. A.
Dubrovskiy, A. A.
Volkov, N. V.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036, Russian Federation
Siberian Federal University, Krasnoyarsk 660041, Russian Federation

Доп.точки доступа:
Shaykhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Popkov, S. I.; Попков, Сергей Иванович; Semenov, S. V.; Семенов, Сергей Васильевич; Balaev, D. A.; Балаев, Дмитрий Александрович; Dubrovskiy, A. A.; Дубровский, Андрей Александрович; Sablina, K. A.; Саблина, Клара Александровна; Sapronova, N. V.; Volkov, N. V.; Волков, Никита Валентинович

/ S. G. Ovchinnikov [et al.] // J. Exp. Theor. Phys. - 2010. - Vol. 111, Is. 1. - P. 104-113, DOI 10.1134/S1063776110070101. - Cited References: 48. - This study was financially supported by the Russian Foundation for Basic Research (project nos. 09-02-01224 and 09-02-00127) and under the program "Quantum Physics of Condensed Media" of the Presidium of the Russian Academy of Sciences (project no. 5.7). . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: We report on the results of measurements of anisotropic resistivity of RBa(2)Cu(3)O(6 + x) (R = Tm, Lu) high-temperature superconducting single crystals in a wide range of doping levels, indicating a nontrivial effect of magnetic order on the electronic properties of cuprates. In particular, our results visually demonstrate the crossover from the state with moderate anisotropy of resistivity rho (c) /rho (ab) similar to 30 to a strongly anisotropic state with rho (c) /rho (ab) similar to 7 x 10(3) upon cooling as well as upon a decrease in the hole concentration in the CuO(2) planes. It is also shown that anisotropy is sensitive to the magnetic state of CuO(2) planes and attains its maximum value after the establishment of the long-range antiferromagnetic order. The results are discussed in the framework of the theory based on the t-t'-taEuro(3)-J model of CuO(2) layers taking into account strong electron correlations and short-range magnetic order. In this theory, anomalies of spin correlators and Fermi surface topology for a critical hole concentration of p* a parts per thousand 0.24 are demonstrated. The concentration dependence of the charge carrier energy indicates partial suppression of energy due to the emergence of a pseudogap at p < p*. This theory explains both the experimentally observed sensitivity of anisotropy in conductivity to the establishment of the antiferromagnetic order and the absence of anomalies in the temperature dependence of resistivity rho (ab) (T) in the vicinity of the N,el temperature.

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Держатели документа:
[Ovchinnikov, S. G.
Korshunov, M. M.] Russian Acad Sci, Kirenskii Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Korshunov, M. M.] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
[Kozeeva, L. P.
Lavrov, A. N.] Russian Acad Sci, Nikolaev Inst Inorgan Chem, Siberian Branch, Novosibirsk 630090, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Siberian Federal University, Krasnoyarsk 660041, Russian Federation
Department of Physics, University of Florida, Gainesville, FL 32611, United States
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Korshunov, M. M.; Коршунов, Максим Михайлович; Kozeeva, L. P.; Lavrov, A. N.; Лавров, Александр Николаевич

/ S. G. Ovchinnikov, E. I. Shneyder // J. Supercond. Nov. Magn. - 2010. - Vol. 23, Is. 5. - P. 733-736, DOI 10.1007/s10948-009-0633-z. - Cited References: 26. - This work is supported by the Presidium RAS program N 7 "Quantum physics of condensed matter," the integration project SORAN-UrORAN N 40, and the RFFI Grant 09-02-00127. . - ISSN 1557-1939РУБ Physics, Applied + Physics, Condensed Matter

Аннотация: We consider magnetic mechanism of superconducting pairing in the effective low energy t - t' - t '' - J* model with all parameters calculated ab initio. Interaction of strongly correlated electrons with different phonon modes is also incorporated. In a BCS type theory, the d(x2-y2) gap is given by a sum of magnetic and phonon contributions. The main contribution to the only fitting parameter G is determined by a competition of the breathing and buckling modes. Fitting the parameter G from the isotope effect, we obtain that magnetic and phonon contributions to the critical temperature T-c work together and are of the same order of magnitude.

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Держатели документа:
[Ovchinnikov, S. G.
Shneyder, E. I.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Shneyder, E. I.] Reshetnev Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Siberian Federal University, 660041 Krasnoyarsk, Russian Federation
Reshetnev Siberian State Aerospace University, 660014 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Shneyder, E. I.; Шнейдер, Елена Игоревна; Овчинников, Сергей Геннадьевич

/ D. A. Balaev [et al.] // J. Exp. Theor. Phys. - 2010. - Vol. 110, Is. 4. - P. 584-593, DOI 10.1134/S1063776110040059. - Cited References: 27. - This study was performed under the program no. 5 of the Russian Academy of Sciences (project no. 7). . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The transport properties (R(T) and R(H) dependences at various values of the transport current in magnetic fields up to 65 kOe) and low-temperature heat capacity in magnetic fields up to 90 kOe of the BaPb0.75Bi0.25O3 superconductor (T-C approximate to 11.3 K) are investigated with the goal of clarifying the mechanisms determining the nonmonotonic behavior and hysteresis of its magnetoresistance R(H). The type of R(H) hysteretic dependences for BaPb0.75Bi0.25O3 is analogous to that observed in granular high-T-c superconductors (HTSCs); however, unlike classical HTSC systems, the field width of the magnetoresistance hysteresis loop for polycrystalline BaPb0.75Bi0.25O3 depends on the transport current. This means that although the mechanisms responsible for the magnetoresistance hysteresis (the influence of the magnetic flux trapped in super-conducting regions on the effective field in Josephson interlayers) are identical in these objects, the transport current in BaPb0.75Bi0.25O3 may considerably affect the diamagnetic response of the superconductor. A considerable effect of transport current on the field in which the R(H) dependences have a peak and exhibit hysterestic properties is observed. Such a behavior can be adequately interpreted using the model of the spatially inhomogeneous superconductor-insulator state proposed by Gorbatsevich et al. [JETP Lett. 52, 95 (1990)]. The nonmonotonic dependence of quantity C/T (C is the heat capacity) on the magnetic field discovered in the present study also agrees with the conclusions based on this model.

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Держатели документа:
[Balaev, D. A.
Dubrovskiy, A. A.
Popkov, S. I.
Shaikhutdinov, K. A.
Petrov, M. I.] Russian Acad Sci, Siberian Branch, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
[Balaev, D. A.
Popkov, S. I.
Shaikhutdinov, K. A.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
[Mart'yanov, O. N.] Russian Acad Sci, Siberian Branch, Boreskov Inst Catalysis, Novosibirsk 630090, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Krasnoyarsk, 660041, Russian Federation
Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russian Federation

Доп.точки доступа:
Balaev, D. A.; Балаев, Дмитрий Александрович; Dubrovskiy, A. A.; Дубровский, Андрей Александрович; Popkov, S. I.; Попков, Сергей Иванович; Shaikhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Mart'yanov, O. N.; Petrov, M. I.; Петров, Михаил Иванович

/ S. N. Varnakov [et al.] // J. Appl. Phys. - 2008. - Vol. 104, Is. 9. - Ст. 94703, DOI 10.1063/1.3005973. - Cited References: 23. - This work was supported by the Russian Academy of Science program "Spintronics," the complex integration project of the Siberian Branch of the Russian Academy of Science. 3.5, the Russian Foundation for Basic Research (Grant No. 07-03-00320), the "Ramon y Cajal" program, and Project No. MAT 2005/01272 of the Spanish Ministry of Education and Science. . - ISSN 0021-8979РУБ Physics, Applied

Аннотация: The magnetization of Fe/Si multilayers, grown by thermal evaporation in an ultrahigh vacuum system, was investigated at high temperatures. Magnetization and its temperature dependence up to a high temperature of 800 K depend on individual Fe layer thickness d(Fe). This dependence is the result of the formation of an Fe-Si interface layer (nonmagnetic phase) during the synthetic procedure. The fraction of this Fe-Si nonmagnetic phase is estimated versus dFe. At temperatures higher than 400 K an irreversible decrease in the magnetization occurs. A quantitative analysis of this irreversible behavior is proposed in terms of an exponential diffusion-like kinetic equation for the reaction that produces the Fe-Si nonmagnetic phase. The coefficients of the rate equation are the activation energy E(a) and the prefactor D(0), which have been determined for different d(Fe). (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3005973]

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Держатели документа:
[Varnakov, S. N.
Komogortsev, S. V.
Ovchinnikov, S. G.] Russian Acad Sci, Kirensky Inst Phys, Siberian Div, Krasnoyarsk 660036, Russia
[Varnakov, S. N.] Siberian Aerosp Univ, Krasnoyarsk 660014, Russia
[Bartolome, J.] Univ Zaragoza, Inst Ciencia Mat Aragon, Dept Fis Mat Condensada, CSIC, E-50009 Zaragoza, Spain
[Sese, J.] Univ Zaragoza, Inst Nanociencia Aragon, Dept Fis Mat Condensada, E-50009 Zaragoza, Spain
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036, Russian Federation
Siberian Aerospace University, pr. im. gazety Krasnoyarskii rabochii 31, Krasnoyarsk 660014, Russian Federation
Instituto de Ciencia de Materiales de Aragon, Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain
Instituto de Nanociencia de Aragon, Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain

Доп.точки доступа:
Varnakov, S. N.; Варнаков, Сергей Николаевич; Komogortsev, S. V.; Комогорцев, Сергей Викторович; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Bartolome, J.; Sese, J.

/ H. H. Klauss [et al.] // Phys. Rev. Lett. - 2008. - Vol. 101, Is. 7. - Ст. 77005, DOI 10.1103/PhysRevLett.101.077005. - Cited References: 28 . - ISSN 0031-9007РУБ Physics, Multidisciplinary

Аннотация: We present a detailed study on the magnetic order in the undoped mother compound LaFeAsO of the recently discovered Fe-based superconductor LaFeAsO(1-x)F(x). In particular, we present local probe measurements of the magnetic properties of LaFeAsO by means of (57)Fe Mossbauer spectroscopy and muon-spin relaxation in zero external field along with magnetization and resistivity studies. These experiments prove a commensurate static magnetic order with a strongly reduced ordered moment of 0.25(5)mu(B) at the iron site below T(N)=138 K, well separated from a structural phase transition at T(S)=156 K. The temperature dependence of the sublattice magnetization is determined and compared to theory. Using a four-band spin density wave model both, the size of the order parameter and the quick saturation below T(N) are reproduced.

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Держатели документа:
[Klauss, H. -H.] Tech Univ Dresden, Inst Festkorperphys, D-01069 Dresden, Germany
Amato, A.] Paul Scherrer Inst, Lab Muon Spin Spect, CH-5232 Villigen, Switzerland
Buechner, B.] Leibniz Inst Festkorper & Weskstoffforsch IFW, D-01171 Dresden, Germany
Kraken, M.] Tech Univ Carolo Wilhelmina Braunschweig, Inst Phys Kondensierten Mat, D-38106 Braunschweig, Germany
Eremin, I.] Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
[Korshunov, M. M.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Eremin, I.] Tech Univ Carolo Wilhelmina Braunschweig, Inst Math Phys, D-38106 Braunschweig, Germany
Institut fur Festkorperphysik, TU Dresden, D-01069 Dresden, Germany
Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
Leibniz-Institut fur Festkorper- und Werkstoffforschung (IFW) Dresden, D-01171 Dresden, Germany
Institut fur Physik der Kondensierten Materie, TU Braunschweig, D-38106 Braunschweig, Germany
Max-Planck-Institut fur Physik Komplexer Systeme, D-01187 Dresden, Germany
L.V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Institut fur Mathematische Physik, TU Braunschweig, D-38106 Braunschweig, Germany

Доп.точки доступа:
Klauss, H. H.; Luetkens, H.; Klingeler, R.; Hess, C.; Litterst, F. J.; Kraken, M.; Korshunov, M. M.; Коршунов, Максим Михайлович; Eremin, I.; Drechsler, S. L.; Khasanov, R.; Amato, A.; Hamann-Borrero, J. E.; Leps, N.; Kondrat, A.; Behr, G.; Werner, J.; Buchner, B.

/ D. A. Balaev [et al.] // Solid State Commun. - 2008. - Vol. 147, Is. 7-8. - P. 284-287, DOI 10.1016/j.ssc.2008.05.044. - Cited References: 17. - This work was Supported by program "Quantum macrophysics" No. 3.4 of RAS and integration project No. 3.4 of SB RAS and in part by KSF, grant 18G011. D.A.B. and A.A.D. acknowledge the Russian Science Support Foundation. . - ISSN 0038-1098РУБ Physics, Condensed Matter

Аннотация: The time evolution of the magnetoresistance of bulk YBCO + CuO composites at T = 4.2 K in constant applied magnetic fields was studied to clarify the mechanism of hysteretic behavior of magnetoresistance R(H) of granular HTSC. The composites represent "model" granular HTSC with weakened Josephson coupling between superconducting (YBCO) crystallites. It was found for the first time that on the ascending branch of R(H) dependence, the resistance at H = const decreased with time while on the descending branch, the resistance increased with time in ail applied constant magnetic field. In the range of low magnetic fields (below the minimum point of the descending branch of the R(H) dependence), the resistance at H const decreased again. Similar measurements performed oil pure polycrystalline YBCO at T = 77.4 K have shown that the behavior of evolution of resistance with time is similar to that observed for the composite. This proves the peculiarity of time evolution of maignetoresistance to be a common feature of granular HTSCs. The behavior revealed is well described by the model Of granular HTSC, where the intergrain media is in an effective magnetic field which is the superposition of the external field and the field induced by superconducting grains. The time evolution of resistance reflects the time relaxation of magnetization of HTSC grains due to the intragrain flux Creep Processes. (C) 2008 Elsevier Ltd. All rights reserved.

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Держатели документа:
[Balaev, D. A.
Dubrovskiy, A. A.
Shaykhutdinov, K. A.
Popkov, S. I.
Petrov, M. I.] LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, 660036 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Balaev, D. A.; Балаев, Дмитрий Александрович; Dubrovskiy, A. A.; Дубровский, Андрей Александрович; Shaykhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Popkov, S. I.; Попков, Сергей Иванович; Petrov, M. I.; Петров, Михаил Иванович

/ V. V. Val'kov, V. A. Mitskan // J. Exp. Theor. Phys. - 2007. - Vol. 105, Is. 1. - P. 90-93, DOI 10.1134/S1063776107070199. - Cited References: 10 . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: Magnetic field effect on the structure of the ground state of a two-dimensional quantum Heisenberg magnet is analyzed. A plaquette representation is used to solve the self-consistent problem and calculate the collective excitation spectrum in a magnetic field. Conditions are found for quantum transition between non-magnetic and oblique antiferromagnetic phases. The change in the ground state of the system is associated with disappearance of the gap in the spin excitation spectrum. Effects of frustration and magnetic field on the spectrum are analyzed. A phase diagram of stable singlet and magnetically ordered phases is presented.

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Держатели документа:
Russian Acad Sci, Kirenskii Inst Phys, Siberian Div, Krasnoyarsk 660036, Russia
Krasnoyarsk State Univ, Krasnoyarsk 660075, Russia
Krasnoyarsk State Tech Univ, Krasnoyarsk 660074, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Krasnoyarsk State University, Krasnoyarsk 660075, Russian Federation
Krasnoyarsk State Technical University, Krasnoyarsk 660074, Russian Federation

Доп.точки доступа:
Mitskan, V. A.; Мицкан, Виталий Александрович; Вальков, Валерий Владимирович

/ S. N. Martynov // Phys. Status Solidi B. - 1988. - Vol. 146, Is. 2. - P. 691-696, DOI 10.1002/pssb.2221460229. - Cited References: 18 . - ISSN 0370-1972РУБ Physics, Condensed Matter


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Доп.точки доступа:
Мартынов, Сергей Николаевич

/ V. V. VALKOV, T. A. VALKOVA // Theor. Math. Phys. - 1984. - Vol. 59, Is. 3. - P. 617-625, DOI 10.1007/BF01018202. - Cited References: 18 . - ISSN 0040-5779РУБ Physics, Multidisciplinary + Physics, Mathematical


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Доп.точки доступа:
VALKOVA, T. A.; Val'kov, V. V.

/ V. V. VALKOV, S. G. OVCHINNIKOV // Theor. Math. Phys. - 1982. - Vol. 50, Is. 3. - P. 306-313, DOI 10.1007/BF01016463. - Cited References: 32 . - ISSN 0040-5779РУБ Physics, Multidisciplinary + Physics, Mathematical


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Доп.точки доступа:
OVCHINNIKOV, S. G.; Овчинников, Сергей Геннадьевич; Val'kov, V. V.

/ E. I. Shneyder, S. G. Ovchinnikov // J. Exp. Theor. Phys. - 2009. - Vol. 109, Is. 6. - P. 1017-1021, DOI 10.1134/S1063776109120139. - Cited References: 42. - This study was financed under programs 5.7 and "Quantum Physics of Condensed Matter" of the Presidium of the Russian Academy of Sciences, integration project no. 40 of the Siberian Branch and Ural Division of the Russian Academy of Sciences, and the Russian Foundation for Basic Research (project no. 09-02-00127). . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: Peculiarities of the temperature isotope effect in a BCS-type theory describing the exchange and phonon mechanisms of Cooper pairing in a system of strongly correlated electrons are considered. The electron-phonon interaction constant is determined from the fitting of the calculated value of the isotope-effect index to the observed value with the parameters of La(2 - x) Sr (x) CuO(4) obtained from ab initio calculations. The value of this constant indicates that the contribution from the traditional pairing mechanism to the superconducting state is of the same order of magnitude as the contribution from the magnetic mechanism.

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Держатели документа:
[Shneyder, E. I.
Ovchinnikov, S. G.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Shneyder, E. I.] Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Siberian State Aerospace University, Krasnoyarsk, 660014, Russian Federation
Siberian Federal University, Krasnoyarsk, 660041, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Шнейдер, Елена Игоревна; Presidium of the Russian Academy of Sciences [40]; Russian Academy of Sciences; Russian Foundation for Basic Research [09-02-00127]

/ I. . Edelman, J. . Kliava // Phys. Status Solidi B. - 2009. - Vol. 246, Is. 10. - P. 2216-2231, DOI 10.1002/pssb.200945169. - Cited References: 87. - This work is supported in part by RFBR-CNRS joint project, grant No 07-02-92174. We are grateful to E. Petrakovskaja and O. Ivanova for measuring and discussing, respectively, the EMR spectra in thermally treated samples and the FR spectral and magnetic field dependences. . - ISSN 0370-1972РУБ Physics, Condensed Matter

Аннотация: In the first part of this paper we outline the state of the art in the field of magnetic nanoparticles in oxide glasses. We describe the theoretical background of two complementary techniques used for the studies of the state of paramagnetic ions, clusters and magnetic particles in a diamagnetic matrix, viz., magnetooptical Faraday rotation (FR) and electron magnetic resonance (EMIR) and we overview previous results obtained with these techniques for several glass systems. In the second part, we highlight the case of potassium-alumina-borate glasses - a glassy system where doping with paramagnetic oxides results in formation of magnetic particles at very low contents of paramagnetic additions: Fe(2)O(3) and MnO. In the special case when the ratio of the iron and manganese oxides in the charge is 3/2, magnetic nanoparticles with characteristics close to those of manganese ferrite are formed already at the first stage of the glass preparation. After thermal treatment all glasses show FR and EMR spectra attesting to the presence of superparamagnetic nanoparticles, characterized by relatively broad size and shape distributions. The formation of magnetic nanoparticles confers to these glasses magnetic and magnetooptical properties typical of magnetically ordered substances. At the same time, the glasses remain transparent in a part of the visible and near infrared spectral range and display a high FR value. Such properties make them particularly interesting for use as new media for various magneto-optical devices. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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Держатели документа:
[Edelman, Irina] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
[Kliava, Janis] Univ Bordeaux 1, Ctr Phys Mol Opt & Hertzienne, CNRS, UMR 5798, F-33405 Talence, France
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Akademgorodok 38, 660036 Krasnoyarsk, Russian Federation
Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux1-CNRS, UMR 5798, 351 cours de la Liberation, 33405 Talence cedex, France

Доп.точки доступа:
Kliava, J.; RFBR-CNRS [07-02-92174]