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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Fokina V.D., Flerov I.N., Molokeev M.S., Pogoreltsev E.I., Bogdanov E.V., Laptash N.M.
Заглавие : Effect of central cation substitution on the properties and phase transitions in (NH4)3Me(O2)2F4 oxyfluorides
Коллективы : International Seminar on Ferroelastic Physics
Место публикации : The 6th International Seminar on Ferroelastics Physics (ISFP-6): Voronezh, September 22–25, 2009. - С. 43
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Flerov I. N.
Заглавие : Ferroelectric and ferroelastic phase transitions in some oxyfluorides A2AMOxF6-x with elpasolite-cryolite structure
Коллективы : Russia/CIS/Baltic/Japan Symposium on Ferroelectricity
Место публикации : 9th Russai/CIS/Baltic/Japan symposium on ferroelectricity: abstracts book : June 15-19, 2008, Vilnius, Lithuania. - p.113
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Bogdanov E. V., Laptash N. M.
Заглавие : The role of chemical pressure in the formation of the structure and barocaloric properties of complex fluorides and oxyfluorides
Колич.характеристики :14 с
Место публикации : Crystallogr. Rep. - 2023. - Vol. 68, Is. 5. - P.765-778. - ISSN 10637745 (ISSN), DOI 10.1134/S1063774523600485. - ISSN 1562689X (eISSN)
Примечания : Cited References: 67
Аннотация: The role of chemical pressure as an effective tool in the processes of formation of initial and distorted (as a result of structural transformations) phases, thermodynamic properties, and direct and inverse barocaloric effects in some complex oxyfluorides and fluorides with octahedral, tetrahedral, and spherical anion and cation groups in the structure has been studied. It is found that, due to the small temperature hysteresis and high baric sensitivity of materials, the maximum values of absolute and integral barocaloric characteristics can be implemented at low pressures. Correspondingly, the temperature range of reversibility of thermodynamic cycles based on fluorides/oxyfluorides as solid-state coolants can be expanded.
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Вид документа : Однотомное издание
Шифр издания :
Автор(ы) : Flerov I. N., Bogdanov E. V., Gorev M. V.
Заглавие : Barocaloric effect in ferroelastic fluorides and oxyfluorides
Колич.характеристики :23 pp.
Место публикации : Barocaloric effects in the solid-state. Materials and methods/ ed. P. Lloveras: IOP Publishing, 2023. - Chapt. 4. - P.4-1-4-23. - , DOI 10.1088/978-0-7503-4690-0ch4
Примечания : Cited References: 68
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bogdanov E. V., Bondarev V. S., Gorev M. V., Molokeev M. S., Flerov I. N.
Заглавие : Effect of deuteration on phase transitions in (NH4)3VOF5
Место публикации : Phys. Solid State. - 2022. - Vol. 64, Is. 3. - P.394-399. - ISSN 10637834 (ISSN), DOI 10.21883/PSS.2022.03.53195.237. - ISSN 10906460 (eISSN)
Примечания : Библиогр.: 26
Аннотация: The (ND4)3VOF5 crystal was grown with a high degree of deuteration (D≈92%). Structural and thermophysical studies have been carried out, the parameters of phase transitions have been determined. It was found that the deuteration of the ammonium cation in (NH4)3VOF5 led to a change in the chemical pressure, which was accompanied by an increase in the unit cell volume and an increase in the phase transition temperatures. The baric coefficients dTi/dp were determined and the phase T−p diagram (ND4)3VOF5 was constructed. A decrease in the temperature stability of the initial cubic phase Fm3¯m in (ND4)3VOF5, as well as a wedging out of the intermediate monoclinic phase at a lower pressure as compared to (NH4)3VOF5, was found.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bogdanov E. V., Pogoreltsev E. I., Kartashev A. V., Gorev M. V., Molokeev M. S., Mel'nikova S. V., Flerov I. N., Laptash N. M.
Заглавие : Thermodynamic properties of vanadium oxypentafluoride (IV) (NH4)3VOF5
Место публикации : Phys. Solid State. - 2020. - Vol. 62, Is. 7. - P.1271-1279. - ISSN 10637834 (ISSN), DOI 10.1134/S1063783420070057
Примечания : Cited References: 17. - This study was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, and the Krasnoyarsk Territorial Foundation for Support of Scientific and R&D Activity, project no. 18-42-243003 “Effect of Deuteration on Orientational Ordering and Phase Transitions in Ammonium Fluorine-Oxygen Vanadates”
Аннотация: The (NH4)3VOF5 crystals have been synthesized and their homogeneity and single-phase structure has been established by the X-ray diffraction, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy studies. The investigations of the temperature dependences of specific heat, entropy, strain, and pressure susceptibility show the occurrence of three phase transitions caused by the structural transformations in the (NH4)3VOF5 crystals. The T–p phase diagram shows the temperature limits of stability of the crystalline phases implemented in (NH4)3VOF5. The optical and dielectric studies disclose the ferroelastic nature of the phase transitions. An analysis of the experimental data together with the data on the isostructural (NH4)3VO2F4 crystal makes it possible to distinguish the physical properties of oxyfluorides containing vanadium of different valences (IV and V).
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Gorev M. V., Bogdanov E. V., Flerov I. N.
Заглавие : Fluorides and oxyfluorides: successive ferroelastic phase transitions and barocaloric effect
Коллективы : Fall Meeting, European Materials Research Society, European Materials Research Society, Warsaw University of Technology
Место публикации : E-MRS fall meeting: conference programme. - 2019. - С. E.P.2
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Bogdanov E. V.
Заглавие : Complex fluorides and oxyfluorides: successive ferroelastic phase transitions and barocaloric effect
Коллективы : International Symposium on Solid State Chemistry for Applications and Sustainable Development, Sustainable Industrial Processing Summit and Exhibition, FLOGEN Stars Outreach
Место публикации : Tressaud Int. Symp. on Solid State Chem. for Applications and Sustainable Dev.: program. - 2019. - Ст.ChemistryFriPM106. - P.103
Примечания : Cited References: 4
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Mikhaleva E. A., Kartashev A. V., Bondarev V. S.
Заглавие : Caloric Effects in Some Ferroelectric and Ferroelastic Fluorides, Oxyfluorides and Oxides
Коллективы : Russia/CIS/Baltic/Japan Symposium on Ferroelectricity, International Workshop on Relaxor Ferroelectrics
Место публикации : Joint 13th Russia/CIS/Baltic/Japan Symp. on Ferroelectricity and Int. Workshop on Relaxor Ferroelectrics (RCBJSF-IWRF 2016): book of abstracts. - 2016. - Ст.Invite-6
Примечания : References: 4. - The reported study was partially supported by RFBR, research project No. 15-02-02009 a
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bogdanov E. V., Mel'nikova S. V., Pogoreltsev E. I., Molokeev M. S., Flerov I. N.
Заглавие : The structure and phase transitions in oxyfluoride (ND4)2MoO2F4
Место публикации : Solid State Sci.: Elsevier, 2016. - Vol. 61. - P.155-160. - ISSN 12932558 (ISSN), DOI 10.1016/j.solidstatesciences.2016.08.012
Примечания : Cited References: 18. - The authors are grateful to A.G. Kocharova for the synthesis and deuteration of the samples, and to A.A. Sukhovsky and Y.N. Ivanov for the execution of NMR studies to determine the degree of sample deuteration.This study was partially supported by Russian Foundation for Basic Research, project No. 16–32–00201 mol_а.
Ключевые слова (''Своб.индексиров.''): deuterium--heavy water--single crystals--x ray analysis--crystal phasis--deuterations--distorted phasis--oxyfluorides--polarization optics--scanning microcalorimetry--tricritical point--molybdenum oxide
Аннотация: Single crystals of (ND4)2MoO2F4 containing 95% deuterium were produced by repeated recrystallization of (NH4)2MoO2F4 in heavy water. The effect of deuteration on the parameters of successive phase transitions was investigated by differential scanning microcalorimetry and polarization optics. X-ray analysis of the original and distorted phases was performed. It was found that deuteration does not change the sequence of crystal phases typical for (NH4)2MoO2F4, but leads to a shift in the phase transition Cmcm Pnma towards the tricritical point. The mechanism of phase transitions in (ND4)2MoO2F4 was associated with both the ordering and the displacement of atoms. © 2016 Elsevier Masson SAS
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Flerov I. N., Gorev M. V., Bogdanov E. V., Laptash N. M.
Заглавие : Barocaloric effect in ferroelastic fluorides and oxyfluorides
Место публикации : Ferroelectrics: Taylor and Francis, 2016. - Vol. 500, Is. 1. - P.153-163. - ISSN 00150193 (ISSN), DOI 10.1080/00150193.2016.1214525
Примечания : Библиогр.: 33. - The reported study was partially supported by the Russian Foundation for Basic Research (RFBR), research project No. 15-02-02009 a.
Ключевые слова (''Своб.индексиров.''): phase transition--fluorides--oxyfluorides--thermal properties--barocaloric effect
Аннотация: Using the data about the temperature - pressure phase diagram and the phase transition entropy at ambient and high pressure, intensive and extensive barocaloric effects were analyzed in the region of single and successive order-disorder phase transitions in fluorides and oxyfluorides with the elpasolites-cryolite structure. It was found that hydrostatic as well as chemical pressure are the effective tools to change the entropy of compounds with disordered ionic groups or atoms in structure and to realize the significant intensive and extensive barocaloric effects comparable with the values of baro- and magnetocaloric effects, characteristic for materials, considered as promising solid refrigerants. © 2016 Taylor & Francis Group, LLC.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylov A. S., Laptash N. M., Vtyurin A. N., Krylova S. N.
Заглавие : Phase transitions in (NH4)2MoO2F4 crystal
Коллективы : International Symposium on Two-Dimensional Correlation Spectroscopy
Место публикации : J. Mol. Struct.: Elsevier Science, 2016. - Vol. 1124, Special Issue: Novel developments and applications of two-dimensional correlation spectroscopy — A festschrift in honor of professor Isao Noda. - P.125-130. - ISSN 0022-2860, DOI 10.1016/j.molstruc.2016.03.009. - ISSN 1872-8014(eISSN)
Примечания : Cited References:17
Предметные рубрики: OXYFLUORIDE
(NH4)2WO2F4
DISORDER
DIAGRAMS
Ключевые слова (''Своб.индексиров.''): phase transitions--raman high-pressure--two-dimensional correlations--oxyfluorides
Аннотация: The mechanisms of temperature and high pressure phase transitions have been studied by Raman spectroscopy. Room temperature (295 K) experiments under high hydrostatic pressure up to 3.6 GPa for (NH4)(2) MoO2 F-4 have been carried out. Experimental data indicates a phase transition into a new high-pressure phase for (NH4)(2) MoO2 F-4 at 1.2 GPa. This phase transition is related to the ordering anion octahedron groups [MoO2 F-4](2) and is not associated with ammonium group. Raman spectra of small non-oriented crystals ranging from 10 to 350 K have been observed. The experiment shows anion groups [MoO2 F-4](2-) and ammonium in high temperature phase are disordered. The phase transition at T-1 = 269.8 K is of the first-order, close to the tricritical point. The first temperature phase transition is related to the ordering anion octahedron groups [MoO2 F-4](2-). Second phase transitions T-2 = 180 K are associated with the ordering of ammonium. The data presented within this study demonstrate that 2D correlation analysis combined with traditional Raman spectroscopy are powerful tool to study phase transitions in the crystals. (C) 2016 Elsevier B.V. All rights reserved.
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13.

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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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylov A. S., Goryainov S. V., Laptash N. M., Vtyurin A. N., Mel'nikova S. V., Krylova S. N.
Заглавие : Influence of the molecular groups ordering on structural phase transitions in (NH4)2WO2F4 crystal
Место публикации : Cryst. Growth Des.: American Chemical Society, 2014. - Vol. 14, Is. 1. - P.374-380. - ISSN 1528-7483, DOI 10.1021/cg400899m. - ISSN 1528-7505
Примечания : Cited References: 27. - This work was partly supported by the Russian Foundation for the Basic Research project no. 12-02-00056, no. 13-02-00825, and integration project SB RAS no. 28, SS-4828.2012.2.Published as part of the Crystal Growth & Design virtual special issue Anion-controlled New Inorganic Materials.
Предметные рубрики: RAMAN-SCATTERING
NEUTRON-SCATTERING
SOLID-STATE
OXYFLUORIDES
DISORDER
POLAR
ANION
Аннотация: Phase transitions of the (NH4)2WO2F 4 crystal were studied by Raman spectroscopy in the range from 10 to 350 K. The mechanism of two phase transitions at T1 = 201 and T 2 = 160 K was proposed. The significant spectra changes occur in the range corresponding to the W-O vibrations. The first temperature phase transition is due to the ordering of the quasi-octahedral groups [WO 2F4]2- and partial ordering of ammonium groups. Experimental data allow for attributing the first (T1 = 201 K) phase transition to the first order close to the tricritical point. The noticeable changes of the Raman spectrum have been found in the range corresponding to the ammonium vibrations below the temperature T2. The second phase transition is associated with the further ordering of ammonium groups. Room temperature (296 K) experiments have been carried out under high hydrostatic pressure up to 10 GPa. Above 2 GPa, new spectral features appear, allowing for the assumption of the existence of a new high-pressure phase of (NH 4)2WO2F4, which is mainly connected with ordering of the [WO2F4]2- quasi-octahedral groups.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylov A. S., Sofronova S. N., Kolesnikova E. M., Ivanov Y. N., Sukhovsky A. A., Goryainov S. V., Ivanenko A. A., Shestakov N. P., Kocharova A. G., Vtyurin A. N.
Заглавие : Experimental and theoretical methods to study structural phase transition mechanisms in K3WO3F3 oxyfluoride
Коллективы : Russian Foundation for Basic Research [4828.2012.2, 12-02-31205]; Federal Special Program "Scientific and scientific-pedagogical staff of innovative Russia" [8379]
Место публикации : J. Solid State Chem. - 2014. - Vol. 218. - P.32-37. - ISSN 0022-4596, DOI 10.1016/j.jssc.2014.05.028. - ISSN 1095-726X
Примечания : Cited References: 21. - The Authors are grateful to Prof. Zinenko V.I. for constructive discussion of the results. The work has been done with financial support of the Russian Foundation for Basic Research projects nos. 4828.2012.2, 12-02-31205; Federal Special Program "Scientific and scientific-pedagogical staff of innovative Russia" project no. 8379.
Предметные рубрики: LATTICE-DYNAMICS
RAMAN-SCATTERING
ELPASOLITE
(NH4)3WO3F3
SPECTROSCOPY
CRYSTALS
Ключевые слова (''Своб.индексиров.''): raman spectroscopy--ir spectroscopy--nmr spectroscopy--high hydrostatic pressure--oxyfluorides--lattice dynamics calculations
Аннотация: The results of structural phase transitions mechanisms study in K3WO3F3oxyfluoride are represented by different experimental and theoretical methods. The structural phase transition anomalies at T1=452 K and T2=414 K of Raman and IR spectra have been analyzed. Using vibrational spectroscopy methods, the NMR-experiment has been done to clarify the nature of found phase transitions: displacive types or order-disorder types. The model of “disordered” crystal was proposed, and the results of lattice dynamics calculation in frameworks of the generalized Gordon–Kim method of ordered (R3) and “disordered” crystals were compared. The high pressure phases were studied by the Raman technique too.
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16.

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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17.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Atuchin V. V., Isaenko L. I., Kesler V. G., Laptash N. M., Molokeev M. S.
Заглавие : Chemical bonding effect in complex oxyfluorides with transition metals
Коллективы : Russian-French workshop on Nanosciences and Nanotechnologies, Российская академия наук, Сибирское отделение РАН, Институт неорганической химии им. А.В. Николаева Сибирского отделения РАН, Институт катализа им. Г.К. Борескова Сибирского отделения РАН, Институт физики полупроводников им. А.В. Ржанова Сибирского отделения РАН
Место публикации : The 7th Russian-French workshop on Nanosciences and Nanotechnologies: Program and abstract book/ ed. A. V. Okotrub. - 2013. - P.29. - ISBN 978-5-901688-29-8
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Мельникова, Светлана Владимировна, Лапташ Н. М.
Заглавие : Влияние атмосферной влажности на симметрию и фазовые переходы слоистых калиевых оксифторидов K2NbOF5·H2O
Место публикации : Физ. тверд. тела. - 2013. - Т. 55, Вып. 6. - С. 1142-1146
Примечания : Работа выполнена при финансовой поддержке гранта Президента РФ (НШ-4828.2012.2)
Аннотация: Выращены кристаллы K2NbOF5·H2O, проведены поляризационно-оптические исследования, измерены двулучепреломление и углы вращения оптической индикатрисы в интервале температур 100-400 K. Установлено, что при комнатной температуре этот слоистый кристалл в зависимости от степени влажности атмосферы может находиться в трех состояниях: A, B и C, различающихся симметрией и свойствами. Кристалл K2NbOF5·H2O в состоянии A, реализующийся при относительной влажности RH=90-100%, испытывает несобственный сегнетоэластический фазовый переход первого рода P 1=ftrightarrow C2/m, сопровождающийся сильными аномалиями оптических характеристик, двойникованием, появлением сдвиговой деформации x6 при температурах T2 downarrow ＝308 K и T2 uparrow ＝313 K. Наиболее устойчивое состояние K2NbOF5·H2O --- B (RH ＝20-90%) --- сохраняет моноклинную симметрию C2/m в области температур 100-370 K. В сухой атмосфере (RH ＝0-20%) или при T1~370 K кристалл становится безводным (K2NbOF5) с симметрией P4/nmm (состояние C). Различие кристаллов в состояниях A и B объясняется наличием или отсутствием молекул воды в межслоевых пространствах.20-90%) --- сохраняет моноклинную симметрию C2/m в области температур 100-370 K. В сухой атмосфере (RH ＝0-20%) или при T1~370 K кристалл становится безводным (K2NbOF5) с симметрией P4/nmm (состояние C). Различие кристаллов в состояниях A и B объясняется наличием или отсутствием молекул воды в межслоевых пространствах.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mel'nikova S. V., Laptash N. M.
Заглавие : Influence of atmospheric humidity on the symmetry and phase transitions of layered potassium oxyfluorides K2NbOF5 · H2O
Место публикации : Phys. solid state: Springer, 2013. - Vol. 55, Is. 6. - P.1231-1235
Аннотация: Crystals of K2NbOF5 · H2O have been grown, polarization optical investigations have been performed, and the birefringence and rotation angle of the optical indicatrix have been measured in the temperature range 100–400 K. It has been found that, depending on the degree of atmospheric humidity, the layered K2NbOF5 · H2O crystal at room temperature can be in three states, namely, A, B, and C, which differ in symmetry and properties of the crystal. The K2NbOF5 · H2O crystal in the A state exists at a relative humidity RH = 90–100% and undergoes a first-order improper ferroelastic phase transition P 1ˉ ↔ C2/m, which is accompanied by strong anomalies of the optical characteristics, twinning, and shear strain x 6 at temperatures T 2 ↓ = 308 K and T 2 ↑= 313 K. The most stable state of the K2NbOF5 sdH2O crystal is the B state (RH = 20–90%), which retains the monoclinic symmetry C2/m in the temperature range 100–370 K. In a dry atmosphere (RH = 0–20%) or at T 1 ≈ 370 K, the crystal becomes anhydrous (K2NbOF5) with the symmetry P4/nmm (the C state). The difference between the crystals in the states A and B is explained by the presence or absence of water molecules in interlayer spaces.
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