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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mushailov E. S., Kim P. D., Turpanov I. A., Bondarenko G. V., Bondarenko G. N., Mishina S. E.
Заглавие : Multilayer composite epitaxial CuCo single crystals
Место публикации : JETP Letters. - 2000. - Vol. 71, Is. 5. - P.195-197. - ISSN 0021-3640, DOI 10.1134/1.568313
Примечания : Cited References: 10
Предметные рубрики: SUPERLATTICES
DIFFRACTION
FILMS
Аннотация: The ion-plasma spraying method was used to synthesize new phases of metastable atomic-ordered layered CuCo single crystals and single crystals of CucCo1 - c solid solutions via epitaxial layer-by-layer crystallization, and some of their physical properties were studied. (C) 2000 MAIK "Nauka/Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Flerov I. N., Bondarev V. S., Sciau P., Lehmann A. G.
Заглавие : Heat capacity of the PbFe1/2Ta1/2O3 perovskite-like compound
Разночтения заглавия :авие SCOPUS: Heat Capacity of the PbFe1/2Ta1/2O3 Perovskite-Like Compound
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2004. - Vol. 46, Is. 3. - P521-525. - ISSN 1063-7834, DOI 10.1134/1.1687872
Примечания : Cited References: 26
Предметные рубрики: SINGLE-CRYSTALS
PBFE0.5TA0.5O3
FERROELECTRICS
DIFFRACTION
NIOBATE
GROWTH
Аннотация: The heat capacity C-p(T) of the complex perovskite PbFe1/2Ta1/2O3 has been studied using adiabatic calorimetry in the temperature range 150-370 K. Three diffuse anomalies in C-p(T) are found to exist at temperatures T-d approximate to 350 K, T-m approximate to 250-300 K, and T-c approximate to 205 K. The anomalous and the lattice contribution to the heat capacity are separated, and the change in the entropy is determined. The results of the study are discussed jointly with the data on the structure and physical properties of the compound. (C) 2004 MAIK "Nauka / Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Fokina V. D., Molokeev M. S., Vasil'ev A. D., Bovina A. F., Laptash N. M.
Заглавие : Heat capacity, structural disorder, and the phase transition in cryolite (NH4)(3)Ti(O-2)F-5
Разночтения заглавия :авие SCOPUS: Heat capacity, structural disorder, and the phase transition in cryolite (NH4)3Ti(O2)F5
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2006. - Vol. 48, Is. 8. - P1559-1567. - ISSN 1063-7834, DOI 10.1134/S1063783406080221
Примечания : Cited References: 18
Предметные рубрики: PEROVSKITE-LIKE OXYFLUORIDES
CRYSTAL-STRUCTURES
(NH4)(3)TIOF5
(NH4)(3)WO3F3
DIFFRACTION
Аннотация: The heat capacity, T-p phase diagrams, and unit cell parameters of cryolite (NH4)(3)Ti(O-2)F-5 were studied over a wide temperature range. A phase transition was found near 226 K, and its thermodynamic characteristics and their dependence on the crystallization conditions were determined. The coordinates and thermal parameters of atoms in the Fm3m phase were refined. An analysis of the electron density distribution and the transition entropy showed that the mechanism of the structural transition involves, above all, rotation of the Ti(O-2)F-5 octahedra. Possible models of disordering of tetrahedral ammonium groups are considered.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fischer P., Pomjakushin V., Sheptyakov D., Keller L., Janoschek M., Roessli B., Schefer J., Petrakovskii G. A., Bezmaternykh L. N., Temerov V. L., Velikanov D. A.
Заглавие : Simultaneous antiferromagnetic Fe3+ and Nd3+ ordering in NdFe3((BO3)-B-11)(4)
Разночтения заглавия :авие SCOPUS: Simultaneous antiferromagnetic Fe3+ and Nd3+ ordering in NdFe3(11BO3)4
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2006. - Vol. 18, Is. 34. - P.7975-7989. - ISSN 0953-8984, DOI 10.1088/0953-8984/18/34/010
Примечания : Cited References: 20
Предметные рубрики: PHASE-TRANSITION
DIFFRACTION
CRYSTALS
GDFE3(BO3)(4)
SINQ
Ключевые слова (''Своб.индексиров.''): iron compounds--magnetic moments--magnetization--neodymium compounds--neutron diffraction--vectors--crystal-field effects--free ion moment--specific heat measurements--symmetry analysis--antiferromagnetic materials
Аннотация: By means of magnetic susceptibility and specific heat measurements, x-ray and unpolarized neutron diffraction investigations on powder and single-crystal samples, simultaneous long-range antiferromagnetic Fe and Nd ordering in NdFe3((BO3)-B-11)(4) with R32 chemical structure has been found at temperatures below T-N = 30.5(5) K down to 1.6 K. At temperatures down to 19 K the propagation vector is k(hex) = [0, 0, 3/2] and becomes slightly incommensurate at lower temperatures. Combined with symmetry analysis, best powder neutron profile fits are obtained with magnetic spiral configurations with the magnetic moments oriented parallel to the hexagonal basal plane according to the irreducible representations tau(3) in the commensurate case. This is in agreement with the easy directions of magnetization perpendicular to the c-axis as determined by magnetic susceptibility measurements. At 1.6 K the magnetic Fe moment amounts to 4.9 mu(B) B close to the free ion moment of Fe3+. The magnetic Nd3+ moment saturates presumably due to crystal-field effects at 2.7 mu(B).
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fokina V. D., Bogdanov E. V., Pogorel'tsev E. I., Bondarev V. S., Flerov I. N., Laptash N. M.
Заглавие : Calorimetric and dielectric studies of the (NH4)(2)MoO2F4 oxyfluoride
Коллективы :
Разночтения заглавия :авие SCOPUS: Calorimetric and dielectric studies of the (NH4)2MoO2F4 oxyfluoride
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2010. - Vol. 52, Is. 1. - P158-166. - ISSN 1063-7834, DOI 10.1134/S1063783410010282
Примечания : Cited References: 22. - This study was supported by the Russian Foundation for Basic Research ( project no. 09-02-00062).
Предметные рубрики: PHASE-TRANSITIONS
(NH4)(2)WO2F4
DIFFRACTION
MECHANISM
CRYSTALS
Аннотация: The temperature dependences of the heat capacity, dielectric properties, and response to an external pressure and an electric field for the (NH4)(2)MoO2F4 oxyfluoride (space group Cmcm, Z = 4) have been studied. A comparative analysis of the data on the entropy of phase transitions, p-T phase diagrams, permittivity, and anomalous heat capacity in combination with the results of previous studies of the related compounds (NH4)(2)WO2F4 and (ND4)(2)WO2F4 has made it possible to establish that both [MO2F4](2-) anions and ammonium groups play a substantial role in the mechanism and nature of the structural transformations.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Hamann-Borrero J. E., Philipp M., Kataeva O., Zimmermann M. V., Geck J., Klingeler R., Vasiliev A., Bezmaternykh L. N., Buchner B., Hess C.
Заглавие : Nonresonant x-ray magnetic scattering on rare-earth iron borates RFe3(BO3)(4)
Коллективы :
Разночтения заглавия :авие SCOPUS: Nonresonant x-ray magnetic scattering on rare-earth iron borates R Fe 3(BO3)4
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2010. - Vol. 82, Is. 9. - Ст.94411. - ISSN 1098-0121, DOI 10.1103/PhysRevB.82.094411
Примечания : Cited References: 38. - This work was supported by the Deustche Forschungsgemeinschaft, through the Forschergruppe FOR520 (Grant No. HE3439/6) and HASYLAB at the Feyerherm from HMI Berlin and specially to Jorg Strempfer from HASYLAB at DESY in Hamburg for valuable discussions.
Предметные рубрики: SINGLE-CRYSTALS
CROSS-SECTION
GDFE3(BO3)(4)
NDFE3(BO3)(4)
DIFFRACTION
MNF2
Аннотация: Hard x-ray scattering experiments with a photon energy of 100 keV were performed as a function of temperature and applied magnetic field on selected compounds of the RFe3(BO3)4 family. The results show the presence of several diffraction features, in particular, nonresonant magnetic reflections in the magnetically ordered phase and structural reflections that violate the diffraction conditions for the low-temperature phase P3(1)21 of the rare-earth iron borates. The temperature and field dependence of the magnetic superlattice reflections corroborate the magnetic structures of the borate compounds obtained by neutron diffraction. The detailed analysis of the intensity and scattering cross section of the magnetic reflection reveals details of the magnetic structure of these materials such as the spin domain structure of NdFe3(BO3)(4) and GdFe3(BO3)(4). Furthermore we find that the correlation length of the magnetic domains is around 100 angstrom for all the compounds and that the Fe moments are rotated 53 degrees +/- 3 degrees off from the hexagonal basal plane in GdFe3(BO3)(4).
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Fokina V. D., Bovina A. F., Bogdanov E. V., Molokeev M. S., Kocharova A. G., Pogorel'tsev E. I., Laptash N. M.
Заглавие : Mechanism and nature of phase transitions in the (NH4)(3)MoO3F3 oxyfluoride
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2008. - Vol. 50, Is. 3. - P515-524. - ISSN 1063-7834, DOI 10.1134/S1063783408030219
Примечания : Cited References: 13
Предметные рубрики: (NH4)(2)WO2F4
DIFFRACTION
CS
Аннотация: The temperature dependences of the heat capacity, the unit cell parameter, and the permittivity for the (NH4)(3)MoO3F3 cryolite (space group Fm (3) over barm) are investigated. It is revealed that the compound undergoes ferroelectric and ferroelastic structural phase transitions at temperatures of 297 and 205 K, respectively. The mechanism of structural distortions is discussed in terms of the entropy parameters, pressure-temperature phase diagrams, and electron density maps for critical atoms. An analysis is made of the influence of the cation size and shape on the phase transitions in oxyfluorides of the general formula A(2)A'MO3F3 (A,A' = NH4, K; M = Mo, W).
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Bogdanov E. V., Flerov I. N., Kocharova A. G., Laptash N. M.
Заглавие : Investigation of thermal expansion, phase diagrams, and barocaloric effect in the (NH4)(2)WO2F4 and (NH4)(2)MoO2F4 oxyfluorides
Коллективы :
Разночтения заглавия :авие SCOPUS: Investigation of thermal expansion, phase diagrams, and barocaloric effect in the (NH4)2WO2F4 and (NH4)2MoO2F4 oxyfluorides
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2010. - Vol. 52, Is. 1. - P167-175. - ISSN 1063-7834, DOI 10.1134/S1063783410010294
Примечания : Cited References: 27. - This study was performed within the framework of the Interdisciplinary Integration Project no. 34 of the Siberian Branch of the Russian Academy of Sciences and supported by the Krasnoyarsk Regional Science Foundation and the Russian Foundation for Basic Research within the framework of the project "Sibir'" ( grant no. 09-02-98001) and by the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools ( project no. NSh-1011.2008.2).
Предметные рубрики: TRANSITIONS
CRYSTALS
DIFFRACTION
MECHANISM
PRESSURE
Аннотация: The thermal expansion along the principal crystallographic axes of the (NH4)(2)WO2F4 and (NH4)(2)MoO2F4 oxyfluorides has been studied. The anomalous behavior of alpha (i) (T) due to the phase transitions has been revealed at T (1) = 271.4 K and T (2) a parts per thousand 180 K for the molybdate and at T (1) = 201.5 K and T (2) a parts per thousand 161 K for the tungstate. The quantities dT/dp and dT/d sigma (i) , which characterize the dependence of the phase transition temperatures on the hydrostatic and uniaxial pressures, have been determined from analyzing the results of studies of the thermal expansion and heat capacity with the use of the Pippard relations. The p-T and alpha (i) -T phase diagrams reflect different characters of the influence of the pressure on the stability of the initial and distorted phases of the oxyfluorides. The magnitudes of the extensive and intensive barocaloric effects determined in the vicinity of the structural phase transitions are as follows: Delta S (BCE) varies from approximately -10 to -17 J/mol K and Delta T (AD) a parts per thousand 8-17 K for the molybdate and Delta S (BCE) varies from approximately -10 to -17 J/mol K and Delta T (AD) a parts per thousand 8-13 K for the tungstate.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sadreev A. F., Sukhinin Y. V.
Заглавие : Phase transitions in a system of CH3(CH2)(n-1) self-assembled on the Au(111) crystal surface
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 1996. - Vol. 54, Is. 24. - P17966-17973. - ISSN 1098-0121, DOI 10.1103/PhysRevB.54.17966
Примечания : Cited References: 44
Предметные рубрики: ORGANIZED MOLECULAR ASSEMBLIES
ALKYL THIOL MONOLAYERS
STRUCTURAL CHARACTERIZATION
DYNAMICS SIMULATION
DEVILS STAIRCASE
GOLD SURFACES
FILMS
MODEL
CHAIN
DIFFRACTION
Аннотация: The n-alkanethiols CH3(CH2)(n-1) on the crystal surface of gold (111) are considered. Couplings between atoms (C, H) of the n-alkanethiols were modelled by the Morse potential, and couplings between the n-alkanethiols and the crystal surface were modelled by 12-3 potentials. Because of symmetry Z(2) of the n-alkanethiols in a tilted state, the system can be reduced to the Ising model on the triangular lattice, the phase diagram of which can be explicitly considered. Depending on the choice of the coupling parameters, the ordered state of the system may form an incommensurate or 2X1 superstructure. The temperatures of the phase transition, equilibrium tilting, twisting, and azimuthal angles are found to depend on the Morse coupling constants.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Perlepe, Panagiota, Oyarzabal, Itziar, Mailman, Aaron, Yquel, Morgane, Platunov M. S., Dovgaliuk, Iurii, Rouzieres, Mathieu, Negrier, Philippe, Mondieig, Denise, Suturina, Elizaveta A., Dourges, Marie-Anne, Bonhommeau, Sebastien, Musgrave, Rebecca A., Pedersen, Kasper S., Chernyshov, Dmitry, Wilhelm, Fabrice, Rogalev, Andrei, Mathoniere, Corine, Clerac, Rodolphe
Заглавие : Metal-organic magnets with large coercivity and ordering temperatures up to 242°C
Коллективы : University of Bordeaux; Region Nouvelle AquitaineRegion Nouvelle-Aquitaine; Quantum Matter Bordeaux; Centre National de la Recherche Scientifique (CNRS)Centre National de la Recherche Scientifique (CNRS); Basque GovernmentBasque Government; VILLUM FONDEN [15374]; Academy of FinlandAcademy of Finland [289172]
Место публикации : Science. - 2020. - Vol. 370, Is. 6516. - P.587-591. - ISSN 0036-8075, DOI 10.1126/science.abb3861. - ISSN 1095-9203(eISSN)
Примечания : Cited References: 42. - This work was supported by the University of Bordeaux, the Region Nouvelle Aquitaine, Quantum Matter Bordeaux, and the Centre National de la Recherche Scientifique (CNRS). I.O. and R.C. are grateful to the Basque Government for I.O.'s postdoctoral grant. K.S.P. thanks the VILLUM FONDEN for a Villum Young Investigator grant (15374). A.M. thanks JYU and the Academy of Finland (project 289172) for support
Предметные рубрики: ROOM-TEMPERATURE
CHROMIUM
FERROMAGNETISM
DIFFRACTION
COMPLEXES
Аннотация: Magnets derived from inorganic materials (e.g., oxides, rare-earth–based, and intermetallic compounds) are key components of modern technological applications. Despite considerable success in a broad range of applications, these inorganic magnets suffer several drawbacks, including energetically expensive fabrication, limited availability of certain constituent elements, high density, and poor scope for chemical tunability. A promising design strategy for next-generation magnets relies on the versatile coordination chemistry of abundant metal ions and inexpensive organic ligands. Following this approach, we report the general, simple, and efficient synthesis of lightweight, molecule-based magnets by postsynthetic reduction of preassembled coordination networks that incorporate chromium metal ions and pyrazine building blocks. The resulting metal-organic ferrimagnets feature critical temperatures up to 242°C and a 7500-oersted room-temperature coercivity.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Visotin M. A., Tarasov I. A., Fedorov A. S., Varnakov S. N., Ovchinnikov S. G.
Заглавие : Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi2 and Si phases
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [16-13-00060-Pi]
Место публикации : Acta Crystallogr. B. - 2020. - Vol. 76. - P.469-482. - ISSN 2052-5206(eISSN), DOI 10.1107/S2052520620005727
Примечания : Cited References: 85. - The following funding is acknowledged: Russian Science Foundation (grant No. 16-13-00060-Pi).
Предметные рубрики: THERMAL-EXPANSION
BETA-FESI2 FILMS
GROWTH
SILICON
DIFFRACTION
Аннотация: A pure crystallogeometrical approach is proposed for predicting orientation relationships, habit planes and atomic structures of the interfaces between phases, which is applicable to systems of low-symmetry phases and epitaxial thin film growth. The suggested models are verified with the example of epitaxial growth of α-, γ- and β-FeSi2 silicide thin films on silicon substrates. The density of near-coincidence sites is shown to have a decisive role in the determination of epitaxial thin film orientation and explains the superior quality of β-FeSi2 thin grown on Si(111) over Si(001) substrates despite larger lattice misfits. Ideal conjunctions for interfaces between the silicide phases are predicted and this allows for utilization of a thin buffer α-FeSi2 layer for oriented growth of β-FeSi2 nanostructures on Si(001). The thermal expansion coefficients are obtained within quasi-harmonic approximation from the DFT calculations to study the influence of temperature on the lattice strains in the derived interfaces. Faster decrease of misfits at the α-FeSi2(001)||Si(001) interface compared to γ-FeSi2(001)||Si(001) elucidates the origins of temperature-driven change of the phase growing on silicon substrates. The proposed approach guides from bulk phase unit cells to the construction of the interface atomic structures and appears to be a powerful tool for the prediction of interfaces between arbitrary phases for subsequent theoretical investigation and epitaxial film synthesis.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fokina V. D., Gorev M. V., Kocharova A. G., Flerov I. N., Pogoreltsev E.I.
Заглавие : Phase transitions and thermodynamic properties of (NH4)(3)VO2F4 cryolite
Место публикации : Solid State Sci. - 2009. - Vol. 11, Is. 4. - P.836-840. - ISSN 1293-2558, DOI 10.1016/j.solidstatesciences.2008.11.004
Примечания : Cited Reference Count: 17. - Гранты: The authors are grateful to Dr. SM. Mel'nikova for the permission to use the unpublished results.; This work was supported by the Russian Foundation for Basic Research (project 06-02-16102).Финансирующая организация: Russian Foundation for Basic Research [06-02-16102]
Предметные рубрики: PEROVSKITE-LIKE OXYFLUORIDES
(NH4)(3)TIOF5
CS
(NH4)(3)WO3F3
DIFFRACTION
(NH4)3VO2F4
ELPASOLITE
METALS
RB
Ключевые слова (''Своб.индексиров.''): oxyfluorides--phase transition--calorimetry--phase diagram--ferroelectricity--calorimetry--ferroelectricity--oxyfluorides--phase diagram--phase transition--calorimetry--ferroelectricity--halide minerals--phase diagrams--sugar (sucrose)--thermodynamic properties--calorimetric measurements--cubic phase--first-order phase transitions--heat capacities--oxyfluorides--phase transition temperatures--pressure dependences--structural transformations--temperature ranges--phase transitions
Аннотация: Calorimetric measurements performed in a wide temperature range on (NH4)(3)VO2F4 have shown the presence of four heat capacity anomalies at T-1 = 438 K, T-2 = 244 K, T-3 = 210.2 K, T-4 = 205.1 K associated with the first order phase transitions. In accordance with the permittivity behavior, the structural transformations are of nonferroelectric nature. Pressure dependence of the phase transition temperatures has been studied by DTA under pressure. The entropy of phase transitions is analyzed mainly in the framework of the orientational disordering of NH4+ and VO2F43- ions in a cubic phase. (C) 2008 Elsevier Masson SAS. All rights reserved.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Smirnova E. S., Alekseeva O. A., Dudka A. P., Verin I. A., Artemov V. V., Lyubutina M. V., Gudim I. A., Frolov K. V., Lyubutin I. S.
Заглавие : Crystal structure of bismuth-containing NdFe3(BO3)4 in the temperature range 20–500 K
Коллективы : Russian Ministry of Science and Higher Education; Ministry of Science and Higher Education within the State assignment FSRC 'Crystallography and Photonics' RAS
Место публикации : Acta Crystallogr. B. - 2022. - Vol. 78, Pt. 1. - P.1-13. - ISSN 2052-5206(eISSN), DOI 10.1107/S205252062101180X
Примечания : Cited References: 44. - This work was performed using the equipment of the Shared Research Center FSRC `Crystallography and Photonics' RAS supported by the Russian Ministry of Science and Higher Education. This work was supported by the Ministry of Science and Higher Education within the State assignment FSRC `Crystallography and Photonics' RAS
Предметные рубрики: MAGNETIC PHASE-TRANSITIONS
UNIT-CELL PARAMETERS
DIFFRACTION
Аннотация: Neodymium iron borate NdFe3(BO3)4 is an intensively studied multiferroic with high electric polarization values controlled by a magnetic field. It is characterized by a large quadratic magnetoelectric effect, rigidity in the base plane and a rather strong piezoelectric effect. In this work, the atomic structure of (Nd0.91Bi0.09)Fe3(BO3)4 was studied by single-crystal X-ray diffraction in the temperature range 20–500 K (space group R32, Z = 3). The Bi atoms found in the composition partially substitute the Nd atoms in the 3a position; they entered the structure due to the growth conditions in the presence of Bi2Mo3O12. It was shown that in the temperature range 20–500 K there is no structural phase transition R32→P3121, which occurs in rare-earth iron borates (RE = Eu–Er, Y) with an effective rare-earth cation radius smaller than that of Nd. The temperature dependence of the unit-cell c parameter reveals a slight increase on cooling below 90 K, which is similar to the results obtained previously for iron borates of Gd, Y and Ho. The atomic distances (Nd,Bi)—O, (Nd,Bi)—B, (Nd,Bi)—Fe, Fe—O, Fe—B and Fe—Fe in the iron chains and between chains decrease steadily with decreasing temperature from 500 to 90 K, whereas the B1(3b)—O distance does not change and the average B2(9e)—O distance increases slightly. There is a uniform decrease in the atomic displacement parameters with decreasing temperature, with a more pronounced decrease for the Nd(3a) and O2(9e) atoms. The O2(9e) atoms are characterized by the maximum atomic displacement parameters and the most elongated atomic displacement ellipsoids. The characteristic Debye and Einstein temperatures, and the static component in the atomic displacements were determined for cations using multi-temperature diffraction data. It was shown that the Nd cations have the weakest bonds with the surrounding atoms and the B cations have the strongest.
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14.

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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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S., Samoilo A. S., Atuchin V. V.
Заглавие : Influence of alkyl substituents in 1,3-diethyl-2-thiobarbituric acid on the coordination environment in M(H2O)2(1,3-diethyl-2-thiobarbiturate)2 M = Ca2+, Sr2+
Место публикации : J. Coord. Chem.: Taylor & Francis, 2016. - Vol. 69, Is. 6. - P.957-965. - ISSN 00958972 (ISSN), DOI 10.1080/00958972.2016.1149168
Примечания : Cited References: 42. - The study was carried out within the public task of the Ministry of Education and Science of the Russian Federation for research engineering of the Siberian Federal University in 2015-2016. V.V.A. is grateful to the Ministry of Education and Science of the Russian Federation for the financial support of the investigation.
Предметные рубрики: CRYSTAL-STRUCTURE
2-THIOBARBITURIC ACID
STRUCTURAL-CHARACTERIZATION
THIOBARBITURIC ACID
THERMAL-PROPERTIES
HYDROGEN-BOND
COMPLEXES
DIFFRACTION
NETWORKS
POLYMERS
Ключевые слова (''Своб.индексиров.''): 1,3-diethyl-2-thiobarbituric acid--alkaline earth metals--coordination compound--x-ray diffraction--thermal analysis
Аннотация: Two new isostructural complexes, [Ca(H2O)2(μ2-Detba-O,O′)2]n (1) and [Sr(H2O)2(μ2-Detba-O,O′)2]n (2) (HDetba = 1,3-diethyl-2-thiobarbituric acid), were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC, FT-IR, and emission spectroscopy. The single-crystal X-ray diffraction data revealed that 1 and 2 are polymeric where M2+ (M = Ca, Sr) is a six-coordinate octahedral binding four Detba− ions and two water molecules. The octahedra are linked through bridging Detba− ions forming a 2-D layer. Two intermolecular hydrogen bonds O–H…S in the crystal form a 3-D net. The comparison of M(Detba)2 and M(Htba)2 (H2tba = 2-thiobarbituric acid) structures showed that the coordination number of metals in M(Detba)2 does not exceed six and there are no π–π interactions, unlike compounds with Htba−; Detba− ions are only bridges in HDetba coordination compounds. Thermal decomposition of 1 and 2 includes dehydration, which mainly ends at 200 °C, and organic ligand oxidation at 300–350 °C with a release of CO2, SO2, H2O, NH3, and isocyanate. Upon excitation at 220 nm, 1 and 2 exhibit an intense emission maximum at 557 nm.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang, Naizheng, Jiang, Xingxing, Molokeev M. S., Song, Gaomin, Guo, Shibin, Huang, Rongjin, Li, Laifeng, Wu, Yicheng, Lin, Zheshuai
Заглавие : Linear Zero Thermal Expansion in a Deep-Ultraviolet Transparent Crystal of BPO4 with Cristobalite-like Structure
Коллективы : National Scientific Foundations of China [51872297, 51702330, 51802321, 51890864]; Fujian Institute of Innovation [FJCXY18010201]; Youth Innovation Promotion Association in CAS [2017035]
Место публикации : Cryst. Growth Des. - 2019. - Vol. 19, Is. 6. - P.3109-3112. - ISSN 1528-7483, DOI 10.1021/acs.cgd.9b00361. - ISSN 1528-7505(eISSN)
Примечания : Cited References: 32. - This work was supported by the National Scientific Foundations of China (Grants 51872297, 51702330, 51802321 and 51890864) and Fujian Institute of Innovation (FJCXY18010201) in CAS, and the Youth Innovation Promotion Association in CAS (outstanding member for Z.L. and Grant 2017035 for X.J.).
Предметные рубрики: PHASE-TRANSITION
DIFFRACTION
QUARTZ
Аннотация: We report the discovery of the zero thermal expansion (ZTE) effect in BPO4, a famous deep-ultraviolet (DUV) optical material with cristobalite-like structure. It is revealed that BPO4 has a linear ZTE coefficient of -0.16(5) MK-1 along the c-axis as temperature increases from 13 to 300 K, which originates from the subtle counterbalance between the rotation-induced expansion and contraction effects among BO4 and PO4 groups. BPO4 is a unique DUV cristobalite-like material exhibiting the linear ZTE behavior.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Udod L. V., Sitnikov M. N., Molokeev M. S., Tarasova L. S., Yanushkevich K. I.
Заглавие : Magnetic, dielectric, and transport properties of bismuth pyrostannate Bi2(Sn0.9Mn0.1)2O7
Коллективы : Russian Foundation for Basic Researchers; Government of the Krasnoyarsk Region; Krasnoyarsk regional Foundation for Support of Scientific and Scientific-Engineering activity [18-52-00045 Bel_a]
Место публикации : Phys. Solid State. - 2017. - Vol. 59, Is. 11. - P.2268-2273. - ISSN 1063-7834, DOI 10.1134/S1063783417110038. - ISSN 1090-6460(eISSN)
Примечания : Cited References:20. - This work was supported by the Russian Foundation for Basic Researchers, the Government of the Krasnoyarsk Region, the Krasnoyarsk regional Foundation for Support of Scientific and Scientific-Engineering activity in the framework of the scientific projects no. 18-52-00045 Bel_a.
Предметные рубрики: BI2SN2O7
POLYMORPHISM
DIFFRACTION
Аннотация: The effect of replacing manganese ions on the structural, dielectric, transport, and magnetic properties of Bi2(Sn0.9Mn0.1)2O7 has been studied and the correlation between them has been determined. The change in the type of thermal processes and the thermopower sign upon polymorphous transitions were detected by differential scanning calorimetry. The paramagnetic Curie temperature and the antiferromagnetic interaction were determined in the martensite and austenite phases. The type of current carriers has been established.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bogdanov E. V., Vasil'ev A. D., Flerov I. N., Laptash N. M.
Заглавие : Effect of cation substitution in fluorine-oxygen molybdates (NH4)(2-x) A (x) MoO2F4
Разночтения заглавия :авие SCOPUS: Effect of cation substitution in fluorine-oxygen molybdates (NH4)2 - xAxMoO2F4
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 53, Is. 2. - P303-308. - ISSN 1063-7834, DOI 10.1134/S1063783411020065
Примечания : Cited References: 11. - This study was supported by the Russian Foundation for Basic Research (project no. 09-02-00062) and the Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools of the Russian Federation (project no. NSh-1011.2008.2).
Предметные рубрики: PHASE-TRANSITIONS
CRYSTALS
(NH4)(2)WO2F4
DIFFRACTION
OXYFLUORIDE
MECHANISM
DISORDER
Аннотация: Thermophysical and structural studies of (NH4)(2 - x) A (x) MoO2F4 (A = Cs, Rb, K) solid solutions of oxyfluorides have been performed. The character of the influence of cation substitutions on the stability of the initial phase (space group Cmcm) and on the mechanism of phase transitions has been elucidated.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mel'nikova S. V., Pogoreltsev E. I., Flerov I. N., Laptash N. M.
Заглавие : Unusual sequence of phase transitions in (NH4)3TiF7 detected by optic and calorimetric studies
Коллективы : Russian Foundation for Basic Research [12-02-00056]; Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation [NSh-924.2014.2]
Место публикации : J. Fluor. Chem.: Elsevier Science, 2014. - Vol. 165. - P.14-19. - ISSN 0022-1139, DOI 10.1016/j.jfluchem.2014.05.016. - ISSN 1873-3328
Примечания : Cited References: 13. - This work was supported by Russian Foundation for Basic Research (Grant no. 12-02-00056), and the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation (Grant no. NSh-924.2014.2).
Предметные рубрики: CRYSTAL-STRUCTURE
DIFFRACTION
NH4F
Ключевые слова (''Своб.индексиров.''): cubic fluorides--phase transitions--crystal-optic--calorimetry
Аннотация: For the first time structural transformations were observed for one of the compounds belonging to the family of double salt fluorides A3MeF7 = A2MeF6·AF. Single crystals of (NH4)3TiF7 = (NH4)2TiF6·NH4F were grown by evaporation of the aqueous solution. Polarizing optical observations, heat capacity and birefringence Δn = (no − ne) measurements were performed in a wide temperature range 100–400 K. Two reversible, first order structural phase transitions were found to be followed by an unusual sequence of symmetry changes: cubic (G3) (T2↓ = 287.5 K; T2↑ = 291–310 K) ↔ P4/mnc (G2) (T1↓ = 358.5 K; T1↑ = 360 K) ↔ 4/m (G1). The twin structures observed were described assuming the existence of cubic parent phase G0 with P m 3 ¯ m symmetry.
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20.

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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