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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shi, Xin, Wu, Yong, Wang, Jian Guo, Kimberg V., Zhang, Song Bin
Заглавие : X-ray transient absorption spectroscopy by an ultrashort x-ray-laser pulse in a continuous-wave IR field
Место публикации : Phys. Rev. A. - 2020. - Vol. 101, Is. 2. - Ст.023401. - ISSN 2469-9926, DOI 10.1103/PhysRevA.101.023401. - ISSN 2469-9934(eISSN)
Примечания : Cited References: 56. - Grants from the National Basic Research Program of China (Grant No. 2017YFA0403200), National Natural Science Foundation of China (Grants No. 11604197, No. 11934004, and No. 11974230), the Science Challenge Program of China (Grants No. TZ2018005 and No. TZ2016005), and the Organization Department of CCCPC are acknowledged. V.K. acknowledges financial support from Swedish Research Council within the State Contract of the Ministry of Education and Science of the Russian Federation for Siberian Federal University for Scientific Research in 2017-2019 (Project No. 3.2662.2017)
Предметные рубрики: MOLECULAR NITROGEN
TIME
DYNAMICS
PHASE
SPECTRA
DECAY
Аннотация: X-ray transient absorption spectra (XTAS) of molecules are theoretically investigated in a femtosecond x-ray pump and continuous-wave (cw) infrared (IR)-control scenario. The scheme is exemplified by a CO molecule resonantly pumped into carbon and oxygen core-excited 1s→π∗ states by a weak femtosecond x-ray pulse, while dynamic Stark shifts are induced by the cw IR-control radiation. As a result, significant shoulder structures appear in XTAS showing strong dependence on the phase of IR radiation relative to the envelope of the x-ray pulse. Due to a significant difference in the frequencies of the two pulses, the present XTAS scheme provides much clear interpretation of the dynamic Stark effects as compared to the attosecond UV transient absorption scenario. Within the suggested two-level model, where the total spectrum is decomposed as incoherent superposition of contributions from different vibrational excitations weighted by the Franck-Condon Factors, all spectral structures can be well identified and interpreted in a good agreement with the full-scale molecular simulations. Well-characterized XTAS in the proposed IR-control scheme can be applied for fine phase synchronization between IR and x-ray pulses, highly demanded in modern experiments on x-ray free-electron lasers.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Melnikova S.V., Vasiliev A. D., Voronov V. N., Bovina A. F.
Заглавие : X-ray and optical studies of CsxRb1-xLiSO4 solid solutions
Место публикации : Fiz. Tverd. Tela: MEZHDUNARODNAYA KNIGA, 1995. - Vol. 37, Is. 8. - P.2529-2531. - ISSN 0367-3294
Примечания : Cited References: 6
Предметные рубрики: MIXED-CRYSTALS
PHASE
WOS
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V.
Заглавие : Splitting of the spectrum of fermionic excitations in a topological insulator by charge fluctuations
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [19-02-00348]
Место публикации : JETP Letters. - 2021. - Vol. 114, Is. 12. - P.751-756. - ISSN 0021-3640, DOI 10.1134/S0021364021240097. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 22. - This work was supported by the Russian Foundation for Basic Research (project no. 19-02-00348)
Предметные рубрики: HUBBARD FERMIONS
EDGE STATES
PHASE
SURFACE
Аннотация: It is shown that the intersite Coulomb interaction of electrons in a topological insulator leads to the splitting of the initial energy structure and to the induction of two bands of fluctuation states. As a result, the total spectrum of Fermi excitations of the topological insulator has a four-band structure. The dielectric gap is determined by the energy interval between the bottom of the band of fluctuation states of conduction electrons and the top of the valence band of fluctuation states. Since the band of fluctuation states is narrow, quasiparticles with different effective masses appear.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Zlotnikov A. O.
Заглавие : Effect of the intersite Coulomb interaction on chiral superconductivity at the noncollinear spin ordering
Коллективы : Russian Foundation for Basic Research; Government of the Krasnoyarsk Territory; Krasnoyarsk Territorial Foundation for Support of Scientific and RD Activities [16-02-00073-a, 16-42-243057-r-mol-a]; Complex Program of the Siberian Branch of the Russian Academy of Sciences II.2P [0358-2015-002]; Grant of the President of the Russian Federation [SP-1370.2015.5]
Место публикации : Phys. Solid State. - 2017. - Vol. 59, Is. 11. - P.2120-2126. - ISSN 1063-7834, DOI 10.1134/S1063783417110300. - ISSN 1090-6460(eISSN)
Примечания : Cited References:18. - This study was supported by the Russian Foundation for Basic Research, Government of the Krasnoyarsk Territory, and Krasnoyarsk Territorial Foundation for Support of Scientific and R&D Activities, projects no. 16-02-00073-a and 16-42-243057-r-mol-a and the Complex Program of the Siberian Branch of the Russian Academy of Sciences II.2P, project no. 0358-2015-002. A.O. Zlotnikov is grateful for support of the Grant of the President of the Russian Federation SP-1370.2015.5.
Предметные рубрики: TRIANGULAR LATTICE
MAGNETIC ORDER
COEXISTENCE
PHASE
Аннотация: We investigate the effect of the intersite Coulomb interaction in a planar system with the triangular lattice on the structure of chiral order parameter Δ(p) in the phase of coexisting superconductivity and noncollinear 120° magnetic ordering. It has been established that the Coulomb correlations in this phase initiate the state where the quasi-momentum dependence Δ(p) can be presented as a superposition of the chiral invariants corresponding to the dx2−y2+idxy and px + ipy symmetry types. It is demonstrated that the inclusion of the Coulomb interaction shifts the Δ(p) nodal point positions and, thereby, changes the conditions for a quantum topological transition.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V.
Заглавие : Edge states of an excitonic insulator with the spin-orbit interaction
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [19-02-00348]
Место публикации : JETP Letters. - 2020. - Vol. 111, Is. 11. - P.647-652. - ISSN 0021-3640, DOI 10.1134/S0021364020110107. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 15. - This work was supported by the Russian Foundation for Basic Research (project no. 19-02-00348)
Предметные рубрики: PHASE
ANOMALIES
Аннотация: The effect of the spin-orbit and Coulomb interactions on the symmetry and topological properties of thes, p, d, ands+dphases of an excitonic insulator has been considered by example of the inverted two-band structure of the HgTe quantum well. It has been found that only thepphase has a nontrivial topology, but it is metastable. It has been shown that the exchange interaction between fermions induces the ground state with thes+dsymmetry of the excitonic order parameter. This phase of the excitonic insulator has zero Chern number; nevertheless, edge states occur in the case of open boundaries.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaykhutdinov K. A., Balaev D. A., Popkov S. I., Vasilyev A. D., Martyanov O. N., Petrov M. I.
Заглавие : Thermally activated dissipation in a novel foamed Bi-based oxide superconductor in magnetic fields
Место публикации : Supercond. Sci. Technol.: IOP PUBLISHING LTD, 2007. - Vol. 20, Is. 6. - P491-494. - ISSN 0953-2048, DOI 10.1088/0953-2048/20/6/001
Примечания : Cited References: 20
Предметные рубрики: FLUX
BI2SR2CACU2O8+DELTA
MECHANISM
PHASE
FILMS
Ключевые слова (''Своб.индексиров.''): bismuth compounds--josephson junction devices--magnetic field effects--transport properties--resistive transitions--thermally activated dissipation--oxide superconductors
Аннотация: The transport properties of a novel foamed superconductor Bi1.8Pb0.3Sr1.9Ca2Cu3Ox have been studied. As the analysis of resistive transitions in a magnetic field shows, the dissipation follows a thermally activated flux creep model with the temperature- independent pinning potential in S-N-S-type Josephson junctions.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Flerov I. N., Sciau P., Guillemet-Fritsch S.
Заглавие : Thermal expansion of (Ba1-x La (x) )Ti1-x/4O3 solid solutions
Коллективы : Russian Foundation for Basic Research [07-02-00069]; Russian Federation [NSh-1011.2008.2]
Разночтения заглавия :авие SCOPUS: Thermal expansion of (Ba1 - X la x )Ti 1 - X/4O3 solid solutions
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2009. - Vol. 51, Is. 4. - P790-796. - ISSN 1063-7834, DOI 10.1134/S106378340904026X
Примечания : Cited References: 22. - This work was supported by the Russian Foundation for Basic Research (project no. 07-02-00069) and the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation (grant NSh-1011.2008.2).
Предметные рубрики: CERAMICS
BATIO3
BA(TI1-XZRX)O-3
FERROELECTRICS
CONDUCTIVITY
BEHAVIOR
SYSTEM
PHASE
HEAT
Аннотация: Deformation and the thermal expansion coefficient of ceramic samples of (Ba1 - x La (x) )Ti1 - x/4O3 solid solutions (x = 0, 0.026, 0.036, 0.054) were studied in the temperature range 120-700 K. Based on an analysis of the data obtained, the temperature-composition phase diagram is refined, and the temperature dependence of the polarization is calculated. The results are discussed in combination with the dielectric measurement data.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Flerov I. N., Bondarev V. S., Maglione M., Simon A.
Заглавие : Thermal expansion and permittivity of (Ba1-xBi2x/3)TiO3 solid solutions
Разночтения заглавия :авие SCOPUS: Thermal expansion and permittivity of (Ba 1 - xBi 2x/3)TiO 3 solid solutions
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 53, Is. 10. - P2073-2079. - ISSN 1063-7834, DOI 10.1134/S1063783411100143
Примечания : Cited References: 24. - This study was supported by the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools (grant NSh-4645.2010.2).
Предметные рубрики: BARIUM-TITANATE
CERAMICS
BATIO3
BEHAVIOR
PHASE
FERROELECTRICS
Аннотация: The strain, the thermal expansion coefficient, and the permittivity of ceramic samples of (Ba1 - x Bi-2x/3)TiO3 solid solutions with x = 0, 0.01, 0.03, and 0.05 have been studied in the temperature range 120-700 K. Based on an analysis of the results, the temperature-composition phase diagram has been refined, and the temperature dependence of the polarization has been calculated.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Bandurina O. N., Romanova O. B., Ryabinkina L. I., Balaev A. D., Eremin E. V.
Заглавие : The interrelation of magnetic and dielectric properties of CoxMn1-xS solid solutions
Коллективы :
Место публикации : J. Phys.: Condens. Matter. - 2010. - Vol. 22, Is. 22. - Ст.226006. - ISSN 0953-8984, DOI 10.1088/0953-8984/22/22/226006
Примечания : Cited References: 20. - This work was supported by the Russian Foundation for Basic Research project nos. 08-02-00364-a, 08-02-90031, F08-037, F08-229 and 09-02-00554-a.
Предметные рубрики: POLARIZATION
TRANSITION
PHASE
Аннотация: Magnetization of the cation-substituted CoxMn1-xS sulfides upon cooling in zero and 100 Oe magnetic fields at the temperatures 4-300 K has been measured. Permittivity of these materials at frequencies from 1 to 100 kHz in magnetic and dc electric fields in the 100-300 K temperature range has been determined. Change in the dielectric permittivity under an external magnetic field is found to have a maximum in the temperature ranges of T-1 similar to (110-120 K) and T-2 similar to (230-250 K). Formation of spontaneous magnetic moment and the rise of magnetic susceptibility are revealed at the same temperatures in the CoxMn1-xS solid solutions. Features of the magnetoelectric properties of the sulfides have been explained by orbital ordering.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Patrin G. S., Shiyan Ya. G., Patrin K. G., Yurkin G. Yu.
Заглавие : Synthesis and magnetic properties of [(CoP)soft/NiP/(CoP)hard/NiP]n films
Место публикации : J. Low Temp. Phys.: Springer, 2016. - Vol. 182, Is. 3-4. - P.73-81. - ISSN 00222291 (ISSN), DOI 10.1007/s10909-015-1363-1
Примечания : Cited References: 25. - This study was supported by the Ministry of Education and Science of the Russian Federation for the Siberian Federal University, state Order No. 3.2534.2014/K and the Russian Foundation for Basic Research, Project No. 14-02-00238-a.
Предметные рубрики: Exchange
Phase
Model
Ключевые слова (''Своб.индексиров.''): interlayer coupling--magnetic heterostructure--hysteresis loop--interlayer coupling--magnetic spring
Аннотация: Magnetic interactions in Co–Ni–P multilayers consisting of alternating magnetically soft and magnetically hard layers are experimentally investigated. The variation in the shape of magnetization loops at the conjugation of magnetically soft and magnetically hard layers and the saturation field oscillations with varying number of layer pairs are established. It is demonstrated that insertion of a nonmagnetic spacer significantly affects the magnetization reversal in the structure. It is concluded that in studying the interlayer coupling it is necessary to take into account the biquadratic interaction.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Yakushkin S. S., Dubrovskii A. A., Bukhtiyarova G. A., Shaikhutdinov K. A., Martyanov O. N.
Заглавие : Study of the high-coercivity material based on ε-Fe2O3 nanoparticles in the silica gel matrix
Место публикации : Tech. Phys. Lett.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 42, Is. 4. - P.347-350. - ISSN 10637850 (ISSN), DOI 10.1134/S1063785016040039
Примечания : Cited References: 17. - This study was supported by the Federal Agency for Scientific Organizations of Russia (base budget financing no. V.44.1.15), the Scientific and Educational Center of Energy-Efficient Catalysis at the Novosibirsk State University, and the Russian Foundation for Basic Research (project no. 15-32-50919).
Предметные рубрики: Phase
Field
State
Oxide
Iron
Аннотация: We report the results of investigations of ε-Fe2O3 magnetic nanoparticles obtained by incipient wetness impregnation of silica gel. It was established that the obtained samples with an iron content of 12‒16% mass % containing ε-Fe2O3 nanoparticles with an average size of 10 nm on the silica gel surface exhibit a room-temperature coercivity of about 10 kOe. Along with fabrication simplicity, this fact makes the prepared samples promising for application as a magnetically hard material. © 2016, Pleiades Publishing, Ltd
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zharkov S. M., Moiseenko E. T., Altunin R. R., Nikolaeva N. S., Zhigalov V. S., Myagkov V. G.
Заглавие : Study of solid-state reactions and order-disorder transitions in Pd/α-Fe(001) thin films
Коллективы : Russian Foundation for Basic Research [14-03-00515a]; Ministry of Education and Science of the Russian Federation
Место публикации : JETP Letters. - 2014. - Vol. 99, Is. 7. - P.405-409. - ISSN 0021-3640, DOI 10.1134/S0021364014070145. - ISSN 1090-6487
Примечания : Cited References: 20. - This work was supported in part by the Russian Foundation for Basic Research (project no. 14-03-00515a) and by the Ministry of Education and Science of the Russian Federation (state contract for the Siberian Federal University for 2014).
Предметные рубрики: MAGNETIC-PROPERTIES
PHASE
Fe
Аннотация: The formation of the hard-magnetic ordered L10-FePd phase in thin bilayer Pd/α-Fe(001) films has been experimentally studied. Solid-state reactions initiated by thermal heating in bilayer Pd/α-Fe(001) films with a thickness of 50–60 nm (the atomic ratio Pd: Fe ≈ 50: 50) separated from the substrate have been studied using the in situ electron diffraction methods. It has been shown that the solid-state reaction between the palladium and iron layers in Pd/α-Fe(001) starts at 400°C with the formation of the disordered Fe-Pd phase. At 480°C, the ordered L10-FePd phase is formed. The order-disorder phase transition has been studied. It has been established that the transition of the ordered L10-FePd phase to the disordered FePd phase starts at 725°C. At 740°C, only the disordered FePd phase is present over the whole volume of the film. The observed temperature of the order-disorder phase transition is shifted from the equilibrium value by 35°C to higher temperatures. This effect is assumingly associated with the higher concentration of palladium atoms at the boundaries of the Fe-Pd crystal grains owing to the grain-boundary adsorption.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Flerov I. N., Bondarev V. S., Sciau P.
Заглавие : Studies of the thermodynamic properties of the ordered perovskites Pb2CdWO6 and Pb2YbTaO6 within a broad temperature range
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2002. - Vol. 44, Is. 2. - P353-357. - ISSN 1063-7834, DOI 10.1134/1.1451027
Примечания : Cited References: 18
Предметные рубрики: CRYSTAL-STRUCTURE
PB2COWO6
PB2MGWO6
PHASE
HEAT
Аннотация: This paper reports on measurements of the specific heat of Pb2CdWO6 made at temperatures ranging from 80 to 750 K and of Pb2YbTaO6 within the 350- to 700-K temperature range. First-order phase transitions from the cubic phase at 677.3 and 581 K, respectively, were observed, and their thermodynamic characteristics were determined. The entropy change on the phase transitions is close to Rln4 for both compounds. The results obtained are discussed in terms of the model of position disordering of the lead ions. It was established that below 350 K, Pb2CdWO6 can exist in two states, stable and metastable, depending on the sample thermal prehistory. (C) 2002 MAIK "Nauka/Interperiodica".
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H., Wang L., Molokeev M. S., Hirosaki N., Xie R., Huang Z., Xia Z., Ten Kate O. M., Liu L., Atuchin V. V.
Заглавие : Structure evolution and photoluminescence of Lu3(Al,Mg)2(Al,Si)3O12:Ce3+ phosphors: New yellow-color converters for blue LED-driven solid state lighting
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 28. - P.6855-6863. - ISSN 20507534 (ISSN), DOI 10.1039/c6tc00966b
Примечания : Cited References: 44. - This work was partially supported by the National Natural Science Foundations of China (Grant No. 51511130035, 51272259, 61575182, 51561135015, and 51572232) and the Russian Foundation for Basic Research (Grant No. 15-52-53080). We are also grateful to financial support from the JSPS KAKENHI (No. 15K06448). H. J. thanks the China Scholarship Council (CSC) for scholarship support. V. V. A. was partially supported by the Ministry of Education and Science of the Russian Federation.
Предметные рубрики: WHITE LEDS
LUMINESCENCE PROPERTIES
EMITTING-DIODES
GARNET PHOSPHORS
SUBSTITUTION
Ce3+
PHASE
Ca
Аннотация: This paper reports the development of new phosphors using the chemical unit cosubstituting solid solution design strategy. Starting from Lu3Al5O12, the Al3+-Al3+ couple in respective octahedral and tetrahedral coordination was simultaneously substituted by a Mg2+-Si4+ pair forming the Lu3(Al2-xMgx)(Al3-xSix)O12:Ce3+ (x = 0.5-2.0) series; as a result, the CeO8 polyhedrons were compressed and the emission got red-shifted from green to yellow together with the broadening. The evolution of, the unit cell, the local structural geometry as well as the optical properties of Ce3+ in these garnet creations, in response to the gradual Mg-Si substitution for Al-Al, were studied by combined techniques of structural refinement and luminescence measurements. The new composition Lu2.97Ce0.03Mg0.5Al4Si0.5O12 was comprehensively evaluated regarding its potential application in blue LED-driven solid state white lighting: the maximum emission is at 550 nm under ?ex = 450 nm; the internal and external quantum efficiencies can reach 85% and 49%, respectively; a 1-phosphor-converted wLED lamp fabricated using the as-prepared phosphor exhibits the luminous efficacy of 105 lm W-1, the correlated color temperature of 6164 K and the color rendering index (Ra) of 75.6. The new solid solution composition series is open for further optimization to enhance the competence for commercial consideration. © 2016 The Royal Society of Chemistry.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Dubrovskiy A. A., Balaev A. D., Shaykhutdinov K. A., Bayukov O. A., Pletnev O. N., Yakushkin S. S., Bukhtiyarova G. A., Martyanov O. N.
Заглавие : Size effects in the magnetic properties of ε-Fe2O3 nanoparticles
Место публикации : J. Appl. Phys.: American Institute of Physics, 2015. - Vol. 118, Is. 21. - Ст.213901. - ISSN 00218979 (ISSN), DOI 10.1063/1.4936838
Примечания : Cited References: 41. - We are grateful to Professor Yu. L. Raikher for useful discussions and M. A. Kazakova for the help in sample preparationThis work was supported by Russian Federal Agency of Scientific Organizations (Project No. V.44.1.15) and scientific and educational center of energy-efficient catalysis of NSU
Предметные рубрики: FERROMAGNETIC-RESONANCE
OXIDE NANOPARTICLES
WAVE ABSORBER
IRON
TRANSITION
TEMPERATURE
PARTICLES
PHASE
FNANOWIRES
FIELD
Аннотация: We report the results of comparative analysis of magnetic properties of the systems based on ε-Fe2O3, nanoparticles with different average sizes (from ∼3 to 9 nm) and dispersions. The experimental data for nanoparticles higher than 6-8 nm in size are consistent with the available data, specifically, the transition to the magnetically ordered state occurs at a temperature of ∼500 K and the anomalies of magnetic properties observed in the range of 80-150 K correspond to the magnetic transition. At the same time, Mossbauer and ferromagnetic resonance spectroscopy data as well as the results of static magnetic measurements show that at room temperature all the investigated samples contain ε-Fe2O3 particles that exhibit the superparamagnetic behavior. It was established that the magnetic properties of nanoparticles significantly change with a decrease in their size to ∼6 nm. According to high-resolution electron microscopy and Mossbauer spectroscopy data, the particle structure can be attributed to the ε-modification of trivalent iron oxide; meanwhile, the temperature of the magnetic order onset in these particles is increased, the well-known magnetic transition in the range of 80-150 K does not occur, the crystallographic magnetic anisotropy constant is significantly reduced, and the surface magnetic anisotropy plays a decisive role. This is apparently due to redistribution of cations over crystallographic positions with decreasing particle size, which was established using Mössbauer spectra. As the particle size is decreased and the fraction of surface atoms is increased, the contribution of an additional magnetic subsystem formed in a shell of particles smaller than ∼4 nm becomes significant, which manifests itself in the static magnetic measurements as paramagnetic contribution. © 2015 AIP Publishing LLC.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sandalov I. S., Richter M.
Заглавие : Local gauge invariance versus slave boson-like representations in systems with strongly correlated electrons
Место публикации : Phys. Scr.: ROYAL SWEDISH ACAD SCIENCES, 1996. - Vol. 54, Is. 4. - P410-416. - ISSN 0281-1847, DOI 10.1088/0031-8949/54/4/020
Примечания : Cited References: 38
Предметные рубрики: T-J MODEL
VALENCE-BOND STATE
DIAGRAM TECHNIQUE
ANDERSON MODEL
HUBBARD MODEL
SUPERCONDUCTIVITY
LIMIT
PHASE
Аннотация: The flux phase solutions in the t-J model the gauge theories with Chern-Simons term, promising new exciting physics, are so far obtained only within slave-boson (or fermion) approaches, where local gauge invariance is not taken into account exactly. We inspect the possibility to do this, mainly, in the example of the t-J model The analysis of different parametrizations in the functional representation shows that (i) calculations which take into account constraints for the number of on-site-available states are describing quasiparticles in terms of the wrong local statistics, and contain gauge non-invariant objects; (ii) application of the projection technique in the slave-boson(fermion) representation reproduces the correct statistics, and is exactly equivalent to the conventional diagram technique for Hubbard operators. In the language of slave bosons this means that the Fourier transformation leading to Bloch states should be made only after accounting constraints in the measure of functional integral.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Rotter I., Sadreev A. F.
Заглавие : Singularities caused by coalesced complex eigenvalues of an effective hamilton operator
Разночтения заглавия :авие SCOPUS: Singularities caused by coalesced complex eigenvalues of an effective Hamilton operator
Место публикации : Int. J. Theor. Phys.: SPRINGER/PLENUM PUBLISHERS, 2007. - Vol. 46: 25th International Colloquium on Group Theoretical Methods in Physics (AUG 02-06, 2004, Cocoyoc, MEXICO), Is. 8. - P1914-1928. - ISSN 0020-7748, DOI 10.1007/s10773-006-9328-4
Примечания : Cited References: 38
Предметные рубрики: UNIMOLECULAR REACTION-RATES
EXCEPTIONAL POINTS
OVERLAPPING RESONANCES
NUCLEAR REACTIONS
QUANTUM-SYSTEMS
UNIFIED THEORY
S-MATRIX
CONTINUUM
PHASE
DEGENERACY
Ключевые слова (''Своб.индексиров.''): effective hamilton--complex eigenvalue--quantum dots--branch points--branch points--complex eigenvalue--effective hamilton--quantum dots
Аннотация: The S matrix theory with use of the effective Hamiltonian is sketched and applied to the description of the transmission through double quantum dots. The effective Hamilton operator is non-hermitian, its eigenvalues are complex, the eigenfunctions are bi-orthogonal. In this theory, singularities occur at points where two (or more) eigenvalues of the effective Hamiltonian coalesce. These points are physically meaningful: they separate the scenario of avoided level crossings from that without any crossings in the complex plane. They are branch points in the complex plane. Their geometrical features are different from those of the diabolic points.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Troyanchuk I. O., Bushinsky M. V., Volkov N. V., Sikolenko V., Efimova E. A., Ritter C.
Заглавие : Role of superexchange interactions in the ferromagnetism of manganites
Место публикации : J. Exp. Theor. Phys.: MAIK Nauka-Interperiodica / Springer, 2015. - Vol. 120, Is. 1. - P.97-102. - ISSN 1063, DOI 10.1134/S1063776115010173. - ISSN 10906509(eISSN)
Примечания : Cited References:25. - This work was supported by the Belarussian Foundation for Basic Research, project no. F12SO-026.
Предметные рубрики: PHASE
NMR
Аннотация: Compound La0.7Sr0.3Mn0.85Nb0.15O3, in which manganese ions are in an oxidation state close to 3+, are studied by neutron diffraction and magnetic measurements. This compound is shown to be a ferromagnet with T C = 145 K and a magnetic moment of 3.1 μB/Mn at T = 10 K. No signs of cooperative orbital ordering are detected. When Mg2+ ions substitute for some Nb5+ ions, Mn4+ ions appear but ferromagnetism is not enhanced. An increase in the structural distortions leads to a decrease in the ferromagnetic component. The ferromagnetic state is assumed to be caused by substantial hybridization of the e g orbitals of manganese and oxygen, which increases the positive part of the superexchange interactions.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Goryainov S. V., Krylov A. S., Pan Y. M., Madyukov I. A., Smirnov M. B., Vtyurin A. N.
Заглавие : Raman investigation of hydrostatic and nonhydrostatic compressions of OH- and F-apophyllites up to 8 GPa
Место публикации : J. Raman Spectrosc.: WILEY-BLACKWELL, 2012. - Vol. 43, Is. 3. - P.439-447. - ISSN 0377-0486, DOI 10.1002/jrs.3049
Примечания : Cited References: 18. - This work was supported by the Siberian Division of RAS (Integration Project 109), the Russian Ministry of Science and Education and the CRDF (BRHE - REC-008 grant) and the Russian Foundation for Basic Research (RFBR-11-05-01121).
Предметные рубрики: RADIATION-INDUCED DEFECTS
ALPHA-QUARTZ
ROOM-TEMPERATURE
MEMORY GLASS
PRESSURE
FLUORAPOPHYLLITE
PHASE
MODEL
Ключевые слова (''Своб.индексиров.''): raman spectroscopy--high pressure--apophyllite--layer silicate--amorphization
Аннотация: Layer silicates F- and OH-apophyllites, KCa4Si8O20(F, OH)·8H2O, have been investigated by Raman spectroscopy at hydrostatic and nonhydrostatic pressures up to 8 GPa in diamond anvil cells using a 4 : 1 methanol–ethanol mix as pressure-transmitting medium. Our experiments show that at hydrostatic compression, apophyllites retain their crystalline states (i.e. no amorphization) up to 5 GPa. The wavenumbers of most bands exhibit linear dependences on pressure, except for a few ones, e.g. at 162 and 3565 cm–1 in OH-form (160.5 and 3558 cm–1 in F-form) that show nonlinear dependences. Nonhydrostatic compression with additional uniaxial loading induces amorphization of apophyllites. The majority of the bands in OH-apophyllite decreases markedly in intensity and shows considerable broadening under nonhydrostatic compression up to 3–6 GPa. In addition, the wavenumbers of several bands at nonhydrostatic compression exhibit considerable nonlinear dependences on pressure with strong hysteresis. These bands are mainly associated with vibrations of the interlayer ions and molecules and also of stretching and bending silicate sheets, hence being highly sensitive to the interlayer distance. Finally, we have calculated the lattice dynamics of F-apophyllite and interpreted the majority of bands, and these data are used to explain the complex baric behavior of the bands. Copyright © 2011 John Wiley & Sons, Ltd.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Terent'ev K. Yu., Gokhfel'd D. M., Popkov S. I., Shaikhutdinov K. A., Petrov M. I.
Заглавие : Pinning in a porous high-temperature superconductor Bi2223
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 53, Is. 12. - P2409-2414. - ISSN 1063-7834, DOI 10.1134/S1063783411120250
Примечания : Cited References: 25. - This study was supported by the Ministry of Education and Science of the Russian Federation within the Russian Federal Targeted Program "Scientific and Scientific-Pedagogical Human Resources for the Innovative Russia in 2009-2013" (state contract no. NIR NK-209P) and the Krasnoyarsk Regional Foundation for Support of Research and Scientific-Technical Activities.
Предметные рубрики: II SUPERCONDUCTORS
MAGNETIC-FIELD
TRANSPORT
PHASE
TAPES
Аннотация: The current-voltage characteristics of a porous superconductor Bi(2)Sr(2)Ca(2)Cu(3)O (x) (Bi2223) have been measured at temperatures in the range from 10 to 90 K in magnetic fields of 0-80 kOe. The experimental dependences have been analyzed within the model allowing for pinning by clusters of a normal phase with fractal boundaries, as well as the model taking into account phase transformations of vortex matter. It has been found that the electrical resistance of the superconductor material significantly increases at temperatures of 60-70 K over the entire range of magnetic fields under consideration without changing in the sign of the curvature of the dependence R(I). It has been assumed that this behavior is associated with the specific feature of the pinning in a highly porous high-temperature superconductor, which lies in the fractality of the distribution of pinning centers in a wide range of self-similarity scales. The studied material at the aforementioned temperatures is characterized by the melting of the vortex structure.
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