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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrichkov V. A., Polukeev S. I., Ovchinnikov S. G.
Заглавие : Cation spin and superexchange interaction in oxide materials below and above spin crossover under high pressure
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [18-12-00022]
Место публикации : Phys. Rev. B. - 2020. - Vol. 101, Is. 9. - Ст.094409. - ISSN 2469-9950, DOI 10.1103/PhysRevB.101.094409. - ISSN 2469-9969(eISSN)
Примечания : Cited References: 65. - We acknowledge the support of the Russian Science Foundation through Grant No. 18-12-00022
Предметные рубрики: EXCHANGE INTERACTION
PHASE-TRANSITIONS
STATE
ELECTRON
IRON
Аннотация: We derived simple rules for the sign of 180° superexchange interaction based on the multielectron calculations of the superexchange interaction in the transition metal oxides that are valid both below and above spin crossover under high pressure. The superexchange interaction between two cations in dn configurations is given by a sum of partial contributions related to the electron-hole virtual excitations to the different states of the dn+1 and dn−1 configurations. Using these rules, we have analyzed the sign of the 180° superexchange interaction of a number of oxides with magnetic cations in electron configurations from d2 until d8: the iron, cobalt, chromium, nickel, copper, and manganese oxides with increasing pressure. The most interesting result concerns the magnetic state of cobalt and nickel oxides CoO, Ni2O3 and also La2CoO4, LaNiO3 isostructural to well-known high-TC and colossal magnetoresistance materials. These oxides have a spin 12 at the high pressure. Change of the interaction from antiferromagnetic below spin crossover to ferromagnetic above spin crossover is predicted for oxide materials with cations in d5(FeBO3) and d7(CoO) configurations, while for materials with the other dn configurations spin crossover under high pressure does not change the sign of the 180∘ superexchange interaction.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylov A. S., Krylova S. N., Kopyl, Svitlana, Krylov A. S., Salehli, Ferid, Zelenovskiy, Pavel, Vtyurin A. N., Kholkin, Andrei
Заглавие : Raman spectra of diphenylalanine microtubes: polarisation and temperature effects
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [18-02-00754]; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115F227]; project Portugal-Turkey [TUBITAK/0006/2014]; FCT/MEC [UIDB/50011/2020, UIDP/50011/2020]; FCT (Portugal) through the project "BioPiezo" [PTDC/CTM-CTM/31679/2017 (CENTRO-01-0145-FEDER-031679)]; national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P.
Место публикации : Crystals. - 2020. - Vol. 10, Is. 3. - Ст.224. - ISSN 2073-4352, DOI 10.3390/cryst10030224
Примечания : Cited References: 43. - This research was funded by the Russian Foundation for Basic Research grant number 18-02-00754, F.S. thanks Scientific and Technological Research Council of Turkey for support under Grant Number 115F227. S.Kopyl and A.Kholkin thank the joint project Portugal-Turkey TUBITAK/0006/2014. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC. S.Kopyl, P.Z. and A.Kholkin were partly supported by FCT (Portugal) through the project "BioPiezo"-PTDC/CTM-CTM/31679/2017 (CENTRO-01-0145-FEDER-031679). Part of this work was funded by national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July.
Предметные рубрики: PIEZOELECTRIC PROPERTIES
PHASE-TRANSITIONS
SPECTROSCOPY
SCATTERING
Аннотация: Diphenylalanine microtubes have remarkable physical properties that allow one to use them in electronics. In this work, we measured polarised temperature-dependent Raman spectra in self-assembled diphenylalanine microtubes grown from the solution. We observed the anomalous temperature behaviour of the Raman lines. Their temperature changes were minimal, which required a significant improvement in the resolution and stability of Raman measurements. The anomalies in the behaviour of the spectra at about 178 K, 235 K, 255 K, 278 K, 296 K, 398 K and 412 K were observed. The structural phase transition at 398 K is irreversible. This transition is associated with the release of water molecules from nanochannels. The irreversible phase transition has a temperature range of about 10 K.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shneyder E. I., Nikolaev S. V., Zotova M. V., Kaldin R. A., Ovchinnikov S. G.
Заглавие : Polaron transformations in the realistic model of the strongly correlated electron system
Коллективы : Russian Foundation for Basic Research, Government of Krasnoyarsk Territory; Krasnoyarsk Regional Fund of Science [18-42-240017, 19-42240007]
Место публикации : Phys. Rev. B. - 2020. - Vol. 101, Is. 23. - Ст.235114. - ISSN 2469-9950, DOI 10.1103/PhysRevB.101.235114. - ISSN 2469-9969(eISSN)
Примечания : Cited References: 69. - We acknowledge the stimulating discussions with V. A. Gavrichkov, G. Seibold, and K. I. Kugel. The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science according to the research project "Features of electron-phonon coupling in high-temperature superconductors with strong electronic correlations" No. 18-42-240017 and project "Electronic correlation effects and multiorbital physics in iron-based materials and cuprates" No. 19-42240007.
Предметные рубрики: ANOMALOUS-DISPERSION
PHONON INTERACTION
PHASE-TRANSITIONS
LO PHONONS
Аннотация: Electron-phonon coupling, diagonal in a real space formulation, leads to a polaron paradigm of smoothly varying properties. However, fundamental changes, namely the singular behavior of polarons, occur if off-diagonal pairing is involved into consideration. The study of polaron transformations and related properties of matter is of particular interest for realistic models, since competition between diagonal and off-diagonal electron-phonon contributions in the presence of other strong interactions can result in unconventional behavior of the system. Here we consider a two-dimensional multiband pd model of cuprate superconductors with electron-phonon interaction and analyze the features of the systems that are caused by the competition of diagonal and off-diagonal electron-phonon contributions in the limit of strong electron correlations. Using the polaronic version of the generalized tight-binding method, we describe the evolution of the band structure, Fermi surface, density of states at Fermi level, and phonon spectral function in the space of electron-phonon parameters ranging from weak to strong coupling strength of the adiabatic limit. On the phase diagram of polaron properties we reveal two quantum phase transitions and show how electron-phonon interaction gives rise to Fermi surface transformation (i) from hole pockets to true Fermi arcs and (ii) from hole to electron type of conductivity. We also demonstrate the emergence of new states in the phonon spectral function of the polaron and discuss their origin.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mikhaleva E. A., Flerov I. N., Kartashev A. V., Gorev M. V., Molokeev M. S., Korotkov L. N., Rysiakiewicz-Pasek E.
Заглавие : Specific heat and thermal expansion of triglycine sulfate-porous glass nanocomposites
Коллективы : Russian Foundation for Basic Research [16-32-00092 mol-a]
Место публикации : Phys. Solid State. - 2018. - Vol. 60, Is. 7. - P.1338-1343. - ISSN 1063-7834, DOI 10.1134/S1063783418070181. - ISSN 1090-6460(eISSN)
Примечания : Cited References: 27. - This study was supported by the Russian Foundation for Basic Research, project no. 16-32-00092 mol-a.
Предметные рубрики: PHASE-TRANSITIONS
DIELECTRIC-PROPERTIES
FERROELECTRIC COMPOSITES
Аннотация: The effect of restricted geometry on specific heat capacity and thermal expansion of the triglycine sulfate (TGS)–borosilicate glass composites have been studied first. A decrease in the entropy and temperature of the P21 ↔ P21/m phase transition in the TGS component with decreasing the glass matrix pore diameter at the invariable specific heat and thermal expansion coefficient has been observed. The estimates are indicative of the minor effect of internal pressure on the TGS pressure coefficient dTC/dp in the composites.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mikhaleva E. A., Flerov I. N., Kartashev A. V., Gorev M. V., Bogdanov E. V., Bondarev V. S., Korotkov L. N., Rysiakiewicz-Pasek E.
Заглавие : Effect of a restricted geometry on thermal and dielectric properties of NH4HSO4 ferroelectric
Коллективы : Russia/CIS/Baltic/Japan Symposium on Ferroelectricity , Russian Foundation for Basic Research (RFBR) [16-32-00092 mol_a]
Место публикации : Ferroelectrics. - 2017. - Vol. 513, Is. 1. - P.44-50. - ISSN 0015-0193, DOI 10.1080/00150193.2017.1350436. - ISSN 1563-5112(eISSN)
Примечания : Cited References:17. - The reported study was partially supported by the Russian Foundation for Basic Research (RFBR), research project No. 16-32-00092 mol_a.
Предметные рубрики: PHASE-TRANSITIONS
AMMONIUM
CAPACITY
SULFATE
KH2PO4
Ключевые слова (''Своб.индексиров.''): ferroelectric--phase transition--porous glass--nanocomposite
Аннотация: Heat capacity, thermal dilatation, sensitivity to pressure and permittivity of NH4HSO4 embedded into glass matrices with a pore size of 320 nm and 46 nm were studied. Large difference in the thermal expansion of both glass and ferroelectric leads to a "clamped" state of NH4HSO4 in nanocomposites and to the phase transition temperatures change. The restricted geometry does not effect on the order of successive transformations in NH4HSO4 but is accompanied by a significant reduction in entropy of phase transitions. The behavior of DTA-signal and permittivity show the expansion of the temperature range of the ferroelectric phase under hydrostatic pressure.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pogorel'tsev E. I., Mel'nikova S. V., Kartashev A. V., Gorev M. V., Flerov I. N., Laptash N. M.
Заглавие : Thermal, optical, and dielectric properties of Fluoride Rb2TaF7
Коллективы : Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund [16-42-243001]
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2017. - Vol. 59, Is. 5. - P.986-991. - ISSN 1063-7834, DOI 10.1134/S1063783417050250. - ISSN 1090-6460(eISSN)
Примечания : Cited References:21. - The reported study was funded by the Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the research project no. 16-42-243001.
Предметные рубрики: PHASE-TRANSITIONS
X-RAY
DISORDER
NMR
DIFFRACTION
OXYFLUORIDE
Аннотация: The thermal, optical, and dielectric properties of fluoride Rb2TaF7 were investigated. It was observed that the variation in chemical pressure in fluorides A2+TaF7 caused by the cation substitution of rubidium for ammonium does not affect the ferroelastic nature of structural distortions, but leads to stabilization of the high- and low-temperature phases and enhancement of birefringence. The entropy of the phase transition P4/nmm ↔ Cmma is typical of the shift transformations, which is consistent with a model of the initial and distorted phase structures. The anisotropy of chemical pressure causes the change of signs of the anomalous strain and baric coefficient dT/dp of Rb2TaF7 as compared with the values for its ammonium analog.
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sobol A. A., Shukshin V. E., Zaitsev A. I.
Заглавие : Raman spectroscopy of SrB4O7 single crystals in the temperature range 300–1273 K
Место публикации : Opt. Spectrosc.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 121, Is. 1. - P.25-31. - ISSN 0030400X (ISSN), DOI 10.1134/S0030400X16070201
Примечания : Cited References: 20. - This work was supported by the Russian Foundation for Basic Research, project no. 13-02-00707a.
Предметные рубрики: STRONTIUM TETRABORATE
PHASE-TRANSITIONS
SCATTERING
SPECTRA
Аннотация: The polarized Raman spectra of SrB4O7 (SBO) single crystals are studied in detail in the temperature range of 300–1273 K. The TO, LO, and IO phonon lines of A1, A2, B1, and B2 symmetries of rhombic SBO at 300 K are identified. The behavior of the Raman spectra of SBO crystals is studied upon heating up to their melting. The relation of Raman spectra with the structure of boron–oxygen fragments, as well as the transformation of spectra in the process of melting of SBO crystals, is discussed. © 2016, Pleiades Publishing, Ltd.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Peschanskii A. V., Fomin V. I., Gudim I. A.
Заглавие : Raman scattering in multiferroic SmFe3(BO3)4
Место публикации : Low Temp. Phys.: American Institute of Physics, 2016. - Vol. 42, Is. 6. - P.475-483. - ISSN 1063-777X, DOI 10.1063/1.4954783. - ISSN 1090-6517(eISSN)
Примечания : Cited References:21
Предметные рубрики: SINGLE-CRYSTALS
MAGNETOELASTIC PROPERTIES
PHASE-TRANSITIONS
FERROBORATE
PHONONS
Аннотация: Raman spectrum of single-crystal SmFe3(BO3)4 was studied in the frequency range from 3 to 1500 cm−1 at temperatures 10–300 K. All the A 1 and E phonon modes predicted by the group theory for a given symmetry of the crystal were observed. The magnitudes of splitting between the LO and TO components of polar E phonons were determined. It was found that under the transition to a magnetically ordered phase, the behavior of the intensity of the line corresponding to the A 1 vibrational mode is anomalous. It was shown that at low temperatures the spectrum of two-magnon excitations has a complex shape and is observed with both nondiagonal and diagonal components of the scattering tensor. This complex shape reflects the features in the density of states of the magnetic branches. An estimate of the magnon energy Em at the Brillouin zone boundary gave ∼47 cm−1. The structure of the ground multiplet 6 H 5/2 of a Sm+3 ion in paramagnetic and antiferromagnetic states as well as the effect of the magnetic phase transition on it were studied. Electron-phonon interaction for the electronic excitation at 225 cm−1 was revealed.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Smirnova E. S., Alekseeva O. A., Dudka A. P., Verin I. A., Artemov V. V., Bezmaternykh L. N., Gudim I. A., Frolov K. V., Lyubutin I. S.
Заглавие : Structure of Gd0.95Bi0.05Fe3(BO3)4single crystals at 293 and 90 K
Место публикации : Crystallogr. Rep.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 61, Is. 4. - P.558-565. - ISSN 10637745 (ISSN), DOI 10.1134/S1063774516040192
Примечания : Cited References: 27. - This study was performed using the equipment of the Center of Collective Use of the Shubnikov Institute of Crystallography of the Russian Academy of Sciences and it was supported by the Ministry of Education and Science of the Russian Federation (Project RFMEFI62114X0005) and in part by the Russian Foundation for Basic Research (Grant nos. 14-02-00483 and 14-02-00307) and the Federal Program on Support of Leading Scientific Schools (Grant no. NSh-6617.2016.5).
Предметные рубрики: TRIGONAL GdFe3(BO3)4
PHASE-TRANSITIONS
IRON
Аннотация: The structure of GdFe3(BO3)4 single crystals has been studied by X-ray diffraction at 293 and 90 K. The crystals are grown from a flux in the Bi2Mo3O12–B2O3–Li2MoO4–Gd2O3–Fe2O3 system. The results of chemical analysis and structural study show that these crystals contain bismuth as an impurity. It is found that bismuth atoms are located at gadolinium sites in the structure. A decrease in the temperature is accompanied by a lowering of the symmetry from sp. gr. R32 (at 293 K) to sp. gr. P3121 (at 90 K). The presence of two types of iron chains with different geometries at 90 K promotes a change in the magnetic properties of these crystals with a decrease in the temperature. © 2016, Pleiades Publishing, Inc.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Klimin S. A., Kashchenko M. A., Bezmaternykh L. N.
Заглавие : Spin-phonon and electron-phonon interactions in multiferroic GdFe3(BO3)4 and TbFe3(BO3)4 evidenced by IR reflection spectroscopy
Коллективы : Russian Science Foundation [14-12-01033]; Swiss National Science Foundation (SNSF); Science and Technology cooperation program "Switzerland-Russia" of the University of Geneva
Место публикации : J. Low Temp. Phys.: Springer/Plenum Publishers, 2016. - Vol. 185, Is. 5-6. - P.538-543. - ISSN 0022-2291, DOI 10.1007/s10909-016-1597-6. - ISSN 1573-7357(eISSN)
Примечания : Cited References:19. - The authors thank Alexey Kuzmenko and Marina Popova for fruitful discussions. This paper was supported by the Russian Science Foundation under Grant No. 14-12-01033, by the Swiss National Science Foundation (SNSF), and by the Science and Technology cooperation program "Switzerland-Russia" of the University of Geneva.
Предметные рубрики: PHASE-TRANSITIONS
GdFe3(BO3)4
CRYSTALS
SPECTRUM
Ключевые слова (''Своб.индексиров.''): multiferroics--ir-active phonons--spin-phonon interaction--coupled--electron-phonon mode
Аннотация: We study temperature-dependent polarized reflection spectra of multiferroic GdFe3(BO3)4 and TbFe3(BO3)4 single crystals. Signatures of spin–lattice interactions in both compounds and of a formation of the electron–phonon coupled mode in TbFe3(BO3)4 are discussed.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuzmenko A. M., Mukhin A. A., Ivanov, V. Yu., Komandin G. A., Shuvaev A., Pimenov A., Dziom V., Bezmaternykh L. N., Gudim I. A.
Заглавие : Terahertz spectroscopy of crystal-field transitions in magnetoelectric TmAl3(BO3)4
Коллективы : Russian Foundation for Basic Research [14-02-91000, 15-02-07647, 14-02-00307, 13-02-12442, 15-42-04186]; Sci. school [924.2014.2]; Austrian Science Funds [I815-N16, W-1243, P27098-N27]
Место публикации : Phys. Rev. B: American Physical Society, 2016. - Vol. 94, Is. 17. - Ст.174419. - ISSN 2469-9950, DOI 10.1103/PhysRevB.94.174419. - ISSN 2469-9969(eISSN)
Примечания : Cited References:35. - This work was partially supported by the Russian Foundation for Basic Research (Grants No. 14-02-91000, No. 15-02-07647, No. 14-02-00307, No. 13-02-12442, and No. 15-42-04186), Sci. school-924.2014.2, and by the Austrian Science Funds (Grants No. I815-N16, No. W-1243, and No. P27098-N27).
Предметные рубрики: ELECTRIC POLARIZATION
PHASE-TRANSITIONS
SINGLE-CRYSTALS
Аннотация: Dynamic magnetic properties of magnetoelectric TmAl3(BO3)4 borate have been investigated by terahertz spectroscopy. Crystal-field transitions within the ground multiplet H36 of Tm3+ ions are observed and they are identified as magnetic-dipole transitions from the ground singlet A1 to the next excited doublet E of Tm3+ ions. Unexpected fine structure of the transitions is detected at low temperatures. The new modes are assigned to local distortions of the sites with D3 symmetry by Bi3+ impurities, which resulted in the splitting of the A1→E transition. Two types of locally distorted sites are identified and investigated. The main contribution to the static magnetic susceptibility is shown to be determined by the matrix elements of the observed magnetic transitions. We demonstrate that even in case of local distortions the symmetry of the undistorted crystal is recovered for magnetic and for quadratic magnetoelectric susceptibilities.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mikhaleva E. A., Eremin E. V., Flerov I. N., Kartashev A. V., Sablina K. A., Mikhashenok N. V.
Заглавие : Magnetization and magnetocaloric effect in La0.7Pb0.3MnO3 ceramics and 0.85(La0.7Pb0.3MnO3)–0.15(PbTiO3) composite
Коллективы : Council on Grants from the President of the Russian Federation forSupport of Leading Scientific Schools [NSh-924.2014.2]
Место публикации : J. Mater. Res. - 2015. - Vol. 30, Is. 2. - P.278-285. - ISSN 0884, DOI 10.1557/jmr.2014.369. - ISSN 20445326(eISSN)
Примечания : Cited References:29. - This work was supported by Council on Grants from the President of theRussian Federation for Support of Leading Scientific Schools (Grant No.NSh-924.2014.2).
Предметные рубрики: PHASE-TRANSITIONS
ELECTROCALORIC MATERIALS
Аннотация: The magnetization behavior under temperature and magnetic field variation was investigated for La0.7Pb0.3MnO3 ceramics and ferromagnetic-ferroelectric 0.85(La0.7Pb0.3MnO3)-0.15(PbTiO3) composite. The second-order ferromagnetic phase transition in manganite is shifted to the tricritical point in composite material. Comparison of the intensive caloric effect and the difference between relative cooling powers (RCP) in both materials proves a significant role of intrinsic pressure in elevating caloric efficiency in composite induced by elastic coupling between the grains of LPM and PT components. No temperature change in composite under an electric field of 2 kV/cm associated with electrocaloric effect or indirect magnetoelectric coupling was observed. The effect of magnetic field on some peculiar temperatures is considered. A contribution from pressure generated by magnetic field to baric coefficient dT/dp of ferromagnetic transformation temperature in composite was suggested. The results obtained were analyzed in the framework of the magnetic equation of state and compared with the experimentally measured heat capacity.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Abramova G. M., Schefer, Juerg, Aliouane N., Boehm M., Petrakovskiy G. A., Vorotynov A. M., Gorev M. V., Bovina A. F., Sokolov V. V.
Заглавие : Single-crystal and powder neutron diffraction study of the FeXMn1−XS solid solutions
Место публикации : J. Alloys Compd.: Elsevier Science, 2015. - Vol. 632. - P.563-567. - ISSN 0925, DOI 10.1016/j.jallcom.2015.01.162. - ISSN 18734669(eISSN)DOI 10.1002/chin.201522001
Примечания : Cited References:23. - This study was supported in part by the INTAS project no. 06-1000013-9002 and the CRDF-SB RAS project no. RUP1-7054-KR-11, N 16854.
Предметные рубрики: PHASE-TRANSITIONS
ALPHA-MNS
MAGNETIC STRUCTURES
HIGH-PRESSURE
FEO
Ключевые слова (''Своб.индексиров.''): magnetic semiconductors--neutron diffraction
Аннотация: The α-MnS-based FeXMn1−XS (0 < x < 0.3) solid solutions are synthesized and shown to be new Mott materials with the rock salt structure. Neutron diffraction data show that the chemical-pressure-induced Neel temperature shift from 150 (x = 0) to 200 K (x = 0.29) observed in these materials is accompanied by a decrease in the NaCl-type cubic lattice parameters. It is established that at the symmetry transformation in the compositions with x = 0.25 and 0.29 the structural transition occurs, which is followed by the magnetic transition. These features make the FeXMn1−XS solid solutions interesting for both fundamental study of the interrelation between the magnetic, electrical, and structural properties in MnO-type strongly correlated electron systems and application.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Beisel N. F., Galashov E. N., Mandrik E. M., Molokeev M. S., Yelisseyev A. P., Yusuf A. A., Xia Z.
Заглавие : Pressure-stimulated synthesis and luminescence properties of microcrystalline (Lu,Y)3Al5O12:Ce3+ garnet phosphors
Место публикации : ACS Appl. Mater. Interfaces: American Chemical Society, 2015. - Vol. 7, Is. 47. - P.26235-26243. - ISSN 19448244 (ISSN), DOI 10.1021/acsami.5b08411
Примечания : Cited References: 75. - This work was partly supported by the National Natural Science Foundations of China (Grant Nos. 51272242 and 51511130035) and the Russian Foundation for Basic Research (Grant No. 15-52-53080 GFEN_a). V.V.A. was partly supported by the Ministry of Education and Science of the Russian Federation
Предметные рубрики: LASER MASS-SPECTROMETRY
LIGHT-EMITTING-DIODES
WHITE-LIGHT
SINGLE-CRYSTALS
OPTICAL-PROPERTIES
ELECTRONIC-STRUCTURE
VIBRATIONAL PROPERTIES
PHASE-TRANSITIONS
PARTICLE-SIZE
GROWTH
Ключевые слова (''Своб.индексиров.''): synthesis--pressure--garnet--structure--luminescence--phosphor
Аннотация: The Lu2.98Ce0.01Y0.01Al5O12 and Y2.99Ce0.01Al5O12 phosphors were synthesized by solid state reaction at temperature 1623 K and pressure 1.5 × 107 Pa in (95% N2 + 5% H2) atmosphere. Under the conditions, the compounds crystallize in the form of isolated euhedral partly faceted microcrystals ∼19 μm in size. The crystal structures of the Lu2.98Ce0.01Y0.01Al5O12 and Y2.99Ce0.01Al5O12 garnets have been obtained by Rietveld analysis. The photoluminescence (PL) and X-ray excited luminescence (XL) spectra obtained at room temperature indicate broad asymmetric bands with maxima near 519 and 540 nm for Y2.99Ce0.01Al5O12 and Lu2.98Ce0.01Y0.01Al5O12, respectively. The light source was fabricated using the powder Lu2.98Ce0.01Y0.01Al5O12 phosphor and commercial blue-emitting n-UV LED chips (λex = 450 nm). It is found that the CIE chromaticity coordinates are (x = 0.388, y = 0.563) with the warm white light emission correlated color temperature (CCT) of 6400 K and good luminous efficiency of 110 lm/W. © 2015 American Chemical Society.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavryushkin P. N., Popov Z. I., Litasov K. D., Gavryushkin A.
Заглавие : Unbiased crystal structure prediction of NiSi under high pressure
Место публикации : J. Appl. Crystallogr.: Wiley-Blackwell, 2015. - Vol. 48, No. 3. - P.906-908. - ISSN 0021, DOI 10.1107/S1600576715005488. - ISSN 16005767(eISSN)
Примечания : Cited References:29. - We thank the Information Technology Centre of Novosibirsk State University for providing access to the cluster computational resources. The research was financially supported by the Russian Science Foundation (grant No. 14-17-00601) and performed under the program of the Ministry of Education and Science of Russia (project No. 14.B25.31.0032). The work of ZIP is supported by the Leading Science School program (No. NS-2886.2014.2).
Предметные рубрики: AUGMENTED-WAVE METHOD
PHASE-TRANSITIONS
STABILITY
EQUATIONS
STATE
Ключевые слова (''Своб.индексиров.''): earth's core--pressure--ab initio calculations--fesi--nisi--cosi--mnsi--isomorphism
Аннотация: On the basis of an unbiased structure prediction, it is shown that the stable form of NiSi under pressures of 100 and 200 GPa is the Pmmn structure. Furthermore, a new stable phase has been discovered: the deformed tetragonal CsCl-type structure with a = 2.174 Å and c = 2.69 Å at 400 GPa. Specifically, the sequence of high-pressure phase transitions is the following: the Pmmn structure below 213 GPa, the tetragonal CsCl type in the range 213–522 GPa, and cubic CsCl higher than 522 GPa. As the CsCl-type structure is considered as the model structure of the FeSi compound at the conditions of the Earth's core, this result implies restrictions on the Fe–Ni isomorphic miscibility in FeSi.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Mikhaleva E. A., Gorev M. V., Kartashev A. V.
Заглавие : Caloric and multicaloric effects in oxygen ferroics and multiferroics
Коллективы : Всероссийская конференция по физике сегнетоэлектриков
Место публикации : Phys. Solid State/ Всероссийская конференция по физике сегнетоэлектриков (20 ; 2014 ; 18-22 авг. ; Красноярск): MAIK Nauka-Interperiodica / Springer, 2015. - Vol. 57, Is. 3. - P.429-441. - ISSN 1063, DOI 10.1134/S1063783415030075. - ISSN 10906460(eISSN)
Примечания : Cited References:53. - This study was supported by the Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools of the Russian Federation (grant no. NSh-924.2014.2).
Предметные рубрики: PHASE-TRANSITIONS
MAGNETOCALORIC MATERIALS
ELECTROCALORIC MATERIALS
REFRIGERATION
CERAMICS
OXYFLUORIDES
Аннотация: The main problems of the current state-of-the-art research into the caloric effects observed in oxygen ferroics, multiferroics, and composites, as well as the influence of different factors (anisotropy, dimensional parameters, direct and indirect interferroic interactions) on these effects, have been considered. Possible ways to increase the caloric efficiency of materials have been analyzed.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xia, Zhiguo, Molokeev M. S., Oreshonkov A. S., Atuchin V. V., Liu R. S., Dong C.
Заглавие : Crystal and local structure refinement in Ca2Al3O6F explored by X-ray diffraction and Raman spectroscopy
Место публикации : Phys. Chem. Chem. Phys.: Royal Society of Chemistry, 2014. - Vol. 16, Is. 13. - P.5952-5957. - ISSN 1463-9076, DOI 10.1039/c3cp53816h. - ISSN 1463-9084
Примечания : Cover illustration: Graphical abstract from this article. - Cited References: 34. - This present work was supported by the National Natural Science Foundations of China (Grant No. 51002146, 51272242), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047) and Beijing Youth Excellent Talent Program (YETP0635), and this study was also partially supported by SB RAS, Grant 28.13. Part of the work was supported by the National Science Council of Taiwan under contract No. NSC 101-2113-M-002-014-MY3.
Предметные рубрики: EMITTING OXYFLUORIDE PHOSPHOR
PHASE-TRANSITIONS
SOLID-STATE
FLUORIDES
DIODES
Аннотация: We present a combined structural analysis on the powder of the Ca2Al3O6F phase using X-ray diffraction (XRD) and Raman spectroscopy techniques. The crystal structure of Ca2Al3O6F has been refined in the rhombohedral system, R space group, a = 17.3237(7) Å, c = 7.00017(4) Å, V = 1819.38(2) Å3, Z = 6. The Ca2Al3O6F phase consists of almost ideal AlO4 tetrahedrons linked through corners, Ca2+ ions in voids, and F− ions disordered over 6 sites around the Ca2 ion. The two different Ca sites have also been verified by the photoluminescence spectrum and decay curves using Eu2+ as the probe ion substituted onto the Ca2+ sites. A lattice dynamics simulation based on the simplified version of the Born–Karman potential model has been produced. Calculated Raman phonon modes agree qualitatively well with the experimental data. The calculations show that the strong line at 538 cm−1 (Ag) corresponds to the vibrational mode of a six-membered AlO4 tetrahedrons ring, and the line at 572 cm−1 (Ag) corresponds to the full symmetric vibration of fluorine atoms in the ab crystal plane.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Bondarev V. S., Raevskaya S. I., Ivliev M. P., Raevskii I. P., Flerov I. N.
Заглавие : Studies of the heat capacity and thermal expansion of the Na0.95K0.05NbO3 solid solution
Коллективы : Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools of the Russian Federation [NSh-4828.2012.2]; Russian Foundation for Basic Research [12-02-31799 mol_a]
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2014. - Vol. 56, Is. 2. - P.367-372. - ISSN 1063-7834, DOI 10.1134/S1063783414020115. - ISSN 1090-6460
Примечания : Cited References: 27. - This study was supported by the Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools of the Russian Federation (grant no. NSh-4828.2012.2) and the Russian Foundation for Basic Research (project no. 12-02-31799 mol_a).
Предметные рубрики: SODIUM NIOBATE
PHASE-TRANSITIONS
TEMPERATURE-RANGE
SINGLE-CRYSTALS
KNBO3
FERROELECTRICS
DIFFRACTION
OCTAHEDRA
Аннотация: The heat capacity and thermal expansion of ceramic samples of the Na0.95K0.05NbO3 solid solution have been investigated over a wide temperature range of 100-750 K. The observed anomalies in the heat capacity and thermal expansion at T (4) = 297 K, T (3) = 535 K, T (2) = 665 K, and T (1) a parts per thousand 710 K correspond to the sequences of phase transitions N - Q - G - S - T1. It has been shown that, as a result of the phase transitions, the unit cell volume at T (4) and T (2) decreases, and at T (3) and T (1), increases with increasing temperature. The directions of the shift of the phase transition temperatures induced by hydrostatic pressure have been determined. It has been established that all structural transformations are accompanied by relatively small variations in the entropy. Different mechanisms of the structural distortions have been discussed.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gerasimova Y. V., Oreshonkov A. S., Ivanenko A. A., Molokeev M. S., Isaenko L. I., Flerov I. N., Bogdanov E. V., Gorev M. V., Kartashev A. V., Krylov A. S.
Заглавие : Structural, spectroscopic, and thermophysical investigations of the oxyfluorides CsZnMoO3F3 and CsMnMoO3F3 with the pyrochlore structure
Коллективы : Russian Foundation for Basic Research [12-02-31205_mol_a]; Ministry of Education and Science of the Russian Federation [8379]; Siberian Branch of the Russian Academy of Sciences [28]
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2014. - Vol. 56, Is. 3. - P.599-605. - ISSN 1063-7834, DOI 10.1134/S1063783414030135. - ISSN 1090-6460
Примечания : Cited References: 26. - This study was supported by the Russian Foundation for Basic Research (project no. 12-02-31205_mol_a), the Ministry of Education and Science of the Russian Federation within the framework of the Federal Target Program "Scientific and Scientific-Pedagogical Human Resources for the Innovative Russia" (agreement no. 8379), and the Siberian Branch of the Russian Academy of Sciences (Interdisciplinary Integration Project no. 28).
Предметные рубрики: PHASE-TRANSITIONS
CRYSTAL-STRUCTURE
STATE
Cs
Mo
Аннотация: The structure, infrared and Raman spectra, heat capacity, and thermal expansion have been investigated. It has been shown that, down to liquid-helium temperatures, the cubic pyrochlore structure of the CsMnMoO3F3 and CsZnMoO3F3 oxyfluorides remains stable. The influence of cation substitution on individual features of the properties of the oxyfluorides has been analyzed.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylov A. S., Kolesnikova E. M., Isaenko L. I., Krylova S. N., Vtyurin A. N.
Заглавие : Measurement of Raman-scattering spectra of Rb2KMoO3F3 crystal: Evidence for controllable disorder in the lattice structure
Коллективы : Russian Foundation for Basic Research [11-02-98002-r, 12-02-00056]; integration project SB RAS [28, SS-4828.2012.2]; Federal Special Program "Scientific and scientific-pedagogical staff of innovative Russia" [8379]
Место публикации : Cryst. Growth Des.: American Chemical Society, 2014. - Vol. 14, Is. 3. - P.923-927. - ISSN 1528-7483, DOI 10.1021/cg4008894. - ISSN 1528-7505
Примечания : Cited References: 31. - The authors are grateful to Prof. I. N. Flerov for valuable support and useful discussions. The authors acknowledge stimulating discussions with Dr. S. N. Sofronova and Dr. A. S. Aleksandrovsky. The assistance of Dr. S. Skokov is sincerely appreciated. This work was partly supported by Russian Foundation for Basic Research project nos. 11-02-98002-r and 12-02-00056 and integration project SB RAS no. 28, SS-4828.2012.2 grant, and Federal Special Program "Scientific and scientific-pedagogical staff of innovative Russia" (no. 8379).
Предметные рубрики: PHASE-TRANSITIONS
OXYFLUORIDE
ELPASOLITE
(NH4)3MOO3F3
(NH4)3WO3F3
TEMPERATURE
DYNAMICS
N-2
Cs
Аннотация: The λ-shaped line width broadening anomalies of octahedron group vibrations in Rb2KMoO3F3 disordered crystal have been revealed in the wide temperature range by Raman technique. The line width of Mo-O and Mo-F vibrations in this crystal is connected with the lattice disorder. The dependence of ordering degree passing the phase transition point history has been discovered. Wide temperature-line width area is found below structural phase transition where different lattice disorder can be obtained at a given temperature by varying the rate of sample cooling. The current study demonstrates the ability of a dynamic temperature regime to control ordering processes in crystals. © 2014 American Chemical Society.
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