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Chemical pressure as an effective tool for tuning the structural disordering and barocaloric efficiency of complex fluorides (NH4)3MF7 (M: Sn, Ti, Ge, Si) / I. N. Flerov, M. V. Gorev, E. V. Bogdanov, N. M. Laptash // J. Phys. D: Appl. Phys. - 2024. - Vol. 57, Is. 17. - Ст. 175301, DOI 10.1088/1361-6463/ad211b. - Cited References: 39. - The study was supported by a Grant from the Russian Science Foundation No. 23-22-00115, https://rscf.ru/project/23-22-00115/ . - ISSN 0022-3727. - ISSN 1361-6463
Кл.слова (ненормированные):
fluorides -- phase transformation -- phase diagram -- entropy -- pressure -- barocaloric effect
Аннотация: Double fluoride salts (NH4)3M4+F7 (M4+: Sn, Ti, Ge, Si) demonstrate a high efficiency of using chemical pressure as a tool for control and tuning structural ordering/disordering, sensitivity to hydrostatic pressure, successions of the phase transitions, etc and, as a result, for purposeful variation within a wide range of parameters of barocaloric effect (BCE). The conventional and inverse BCEs near the triple points were found on the T − p phase diagrams, combination of which can be used to construct original cooling cycle in narrow temperature and pressure ranges. Reconstructive transformation between two cubic phases, Pm3-m ↔ Pa3-, realized in (NH4)3SnF7 at atmospheric pressure and in (NH4)3TiF7 at p ˃ 0.4 GPa are characterized by rather low thermal hysteresis, δT0 = 1 K, and a great entropy change, ΔSBCE = 110–152 J (kg · K)−1, depending on the size of the central atom. At above 300–350 K, a contribution to BCE associated with the regular thermal expansion of the crystal lattice becomes comparable to entropy and temperature changes under pressure in the region of the phase transitions. An analysis of the absolute, relative and integral barocaloric characteristics of (NH4)3M4+F7 compounds showed their high competitiveness with respect to other barocaloric materials considered as promising solid-state refrigerants.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, 660074 Krasnoyarsk, Russia
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, 660049 Krasnoyarsk, Russia
Institute of Chemistry, Far Eastern Department of RAS, 690022 Vladivostok, Russia

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Gorev, M. V.; Горев, Михаил Васильевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Laptash, N. M.
}
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Muraev, P. S.
Quantum manifestation of the classical bifurcation in the driven dissipative Bose–Hubbard dimer / P. S. Muraev, D. N. Maksimov, A. R. Kolovsky // Entropy. - 2023. - Vol. 25, Is. 1 : Special Issue: Quantum Chaos—Dedicated to Professor Giulio Casati on the Occasion of His 80th Birthday. - Ст. 117, DOI 10.3390/e25010117. - Cited References: 18. - This work has been supported by Russian Science Foundation through grant N19-12-00167 . - ISSN 1099-4300
Кл.слова (ненормированные):
open quantum system -- non-linear dynamics -- chaotic attractors
Аннотация: We analyze the classical and quantum dynamics of the driven dissipative Bose–Hubbard dimer. Under variation of the driving frequency, the classical system is shown to exhibit a bifurcation to the limit cycle, where its steady-state solution corresponds to periodic oscillation with the frequency unrelated to the driving frequency. This bifurcation is shown to lead to a peculiarity in the stationary single-particle density matrix of the quantum system. The case of the Bose–Hubbard trimer, where the discussed limit cycle bifurcates into a chaotic attractor, is briefly discussed.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
School of Engineering Physics and Radio Electronics, Siberian Federal University, 660041 Krasnoyarsk, Russia
IRC SQC, Siberian Federal University, 660041 Krasnoyarsk, Russia

Доп.точки доступа:
Maksimov, D. N.; Максимов, Дмитрий Николаевич; Kolovsky, A. R.; Коловский, Андрей Радиевич; Мураев, Павел Сергеевич
}
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    Микроструктура и магнитные свойства высоко энтропийных сплавов FeCoNiP-Me (Me=Zn, Zr, W), полученных методов химического осаждения / Л. А. Чеканова, Е. А. Денисова, С. В. Комогорцев [и др.] // Магнитные материалы. Новые технологии : тез. докл. IX Байкал. междунар. конф. BICMM-2023 / чл. прогр. ком.: S. S. Aplesnin [et al.] ; чл. орг. ком. R. S. Iskhakov [et al.]. - Иркутск, 2023. - С. 125-126, DOI 10.26516/978-5-9624-2178-0.2023.1-207. - Библиогр.: 4 . - ISBN 978-5-962402178-0
   Перевод заглавия: Microstructure and magnetic properties of FeCoNiP-Me (Me=Zn, Zr, W) high entropy alloys produced by electroless deposition

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Держатели документа:
Институт физики им. Л. В. Киренского СО РАН
Сибирский федеральный университет
Красноярский научный центр СО РАН

Доп.точки доступа:
Аплеснин, Сергей Степанович \чл. прогр. ком.\; Aplesnin, S. S.; Балаев, Дмитрий Александрович \чл. прогр. ком.\; Balaev, D. A.; Овчинников, Сергей Геннадьевич \чл. прогр. ком.\; Ovchinnikov, S. G.; Исхаков, Рауф Садыкович \чл. орг. ком.\; Iskhakov, R. S.; Чеканова, Лидия Александровна; Chekanova, L. A.; Денисова, Елена Александровна; Denisova, E. A.; Комогорцев, Сергей Викторович; Komogortsev, S. V.; Важенина, Ирина Георгиевна; Vazhenina, I. G.; Исхаков, Рауф Садыкович; Бондаренко, Галина Николаевна; Bondarenko, G. N.; Кох, Д.; Великанов, Дмитрий Анатольевич; Velikanov, D. A.; Немцев, Иван Васильевич; Nemtsev, I. V.; Еремин, Леонид Аркадьевич; Байкальская международная конференция "Магнитные материалы. Новые технологии"(9 ; 2023 ; сент. ; 11-14 ; Байкальск); "Магнитные материалы. Новые технологии", Байкальская международная конференция(9 ; 2023 ; сент. ; 11-14 ; Байкальск); "Magnetic materials. New tecnologies", Baikal International Conference(9 ; 2023 ; Sept. ; 11-14 ; Baikalsk); Иркутский государственный университет
}
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Effect of the size of the central atom on the stability of crystalline phases in solid solutions (NH4)3TixSn1-xF7 / E. V. Bogdanov, E. I. Pogoreltsev, M. V. Gorev [et al.] // J. Solid State Chem. - 2023. - Vol. 328. - Ст. 124373, DOI 10.1016/j.jssc.2023.124373. - Cited References: 20. - The study was supported by a grant from the Russian Science Foundation № 23-22-00115, https://rscf.ru/project/23-22-00115/. - X-ray and dilatometric data and SEM images were obtained using the equipment of the Krasnoyarsk Regional Center for Collective Use of the Federal Research Center — Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences. We are grateful to Dr. A.V. Shabanov for examination of the SEM images . - ISSN 0022-4596. - ISSN 1095-726X
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Heat capacity -- Entropy -- Thermal expansion -- Birefringence -- Solid solution -- Internal pressure
Аннотация: The effect of a change in internal pressure as a result of partial substitution of the central atom on the realization and stability of the initial and distorted crystalline phases in (NH4)3TixSn1-xF7 solid solutions has been studied. It was found that at a Ti concentration in the range of x = 0.15–0.40, the reconstructive transition Pm-3m ↔ Pa-3 is transformed into a sequence of phase transitions Pm-3m ↔ P4/mbm ↔ P4/mnc ↔ Pa-3. In the (NH4)3Ti0.15Sn0.85F7 solid solution, the first-order phase transition between two cubic phases at T0 = 352 K is characterized by a significant volume jump δ(ΔV/V0) ≈ 1 %, comparable with that in (NH4)3SnF7. An increase of the Ti concentration leads to a strong decrease in the stability of the Pm-3m cubic phase: the first tetragonal P4/mbm phase appears in (NH4)3Ti0.4Sn0.6F7 at T0 = 400 K, which proves the existence of the predicted high-temperature cubic phase in (NH4)3TiF7. In solid solutions, a decrease in birefringence and entropy of phase transitions was observed in comparison with the initial compounds with Sn and Ti as central atoms. The role of critical parameters (unit cell volume, temperature, external pressure) in the formation of cubic and distorted phases is discussed.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036, Krasnoyarsk, Russia
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, 660049, Krasnoyarsk, Russia
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, 660074, Krasnoyarsk, Russia
Institute of Chemistry, Far Eastern Department of RAS, 690022, Vladivostok, Russia

Доп.точки доступа:
Bogdanov, E. V.; Богданов, Евгений Витальевич; Pogoreltsev, E. I.; Погорельцев, Евгений Ильич; Gorev, M. V.; Горев, Михаил Васильевич; Mel'nikova, S. V.; Мельникова, Светлана Владимировна; Molokeev, M. S.; Молокеев, Максим Сергеевич; Laptash, N. M.; Flerov, I. N.; Флёров, Игорь Николаевич
}
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Direct and indirect studies of the electrocaloric effect in single crystalline ferrielectric (NH4)2SO4 / V. S. Bondarev, E. A. Mikhaleva, M. V. Gorev, I. N. Flerov // J. Alloys Compd. - 2022. - Vol. 892. - Ст. 162130, DOI 10.1016/j.jallcom.2021.162130. - Cited References: 38. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023) . - ISSN 0925-8388
Кл.слова (ненормированные):
Ferrielectric -- Electrocaloric effect -- Phase transition -- Entropy
Аннотация: The influence of an electric field on the phase transition parameters and the electrocaloric response in ferrielectric (NH4)2SO4 was studied using a universal multifunctional adiabatic calorimeter. The very low sensitivity of the phase transition temperature to the electric field, dT0/dE ≈ 5·10-3 K/(kV/cm), was shown to be the reason for the low maximum value of the intensive electrocaloric effect, ΔTAD, at E = 11 kV/cm: direct and indirect measurements gave the values of 0.01 K and 0.05 K, respectively. However, the extensive electrocaloric response revealed by an analysis of the entropy–temperature–electric field phase diagram was relatively large, with a value of ΔSECE ≈ − 19 J/kg K, due to the significant contribution of a jump in the excess entropy to the total value, δS0/ΔS0 ~ 0.37. An additional irreversible increase in temperature under the electric field was associated with the Joule effect and indicated a significant electrical conductivity of ammonium sulphate.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation

Доп.точки доступа:
Bondarev, V. S.; Бондарев, Виталий Сергеевич; Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Flerov, I. N.; Флёров, Игорь Николаевич
}
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Bogdanov, E. V.
Effect of deuteration on the barocaloric properties of complex vanadates (NH4)3VOxF6−x (x: 1, 2) / E. V. Bogdanov, M. V. Gorev, I. N. Flerov // Solid State Sci. - 2022. - Vol. 133. - Ст. 107022, DOI 10.1016/j.solidstatesciences.2022.107022. - Cited References: 28 . - ISSN 1293-2558
Кл.слова (ненормированные):
Fluorides -- Phase transition -- Entropy -- Barocaloric effect
Аннотация: We report on the analysis of intensive and extensive barocaloric properties and their sensitivity to deuteration of complex oxyfluorides (NH4)3VOxF6−x (x: 1, 2) undergoing a similar sequence of structural phase transitions. Due to the high sensitivity to hydrostatic pressure and the strong disordering of six-coordinated anionic fluoro-oxygen species, (NH4)3VO2F4 and (ND4)3VO2F4 crystals demonstrate the highest barocaloric efficiency at low pressure, p = 0.1 GPa, during the phase transition from the initial cubic phase: barocaloric coefficients reach large values |ΔSBCE|/p ≈ 400 J/(kg K GPa) and ΔTAD/p ≈ 80 K/GPa. Anionic, [VOF5] → [VO2F4], and cationic, [ND4] → [NH4] substitutions are accompanied by a decrease in the disorder of structural units in the cubic phase, which leads to a decrease in changes in entropy and temperature under pressure. The contribution of thermal expansion of the crystal lattice to the total intensive and extensive barocaloric effects is large and amounts to about 30–40%.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Flerov, I. N.; Флёров, Игорь Николаевич; Богданов, Евгений Витальевич
}
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Heat capacity and thermal expansion of nanosized ferroelectric (NH4)2SO4 embedded in borosilicate glasses / E. A. Mikhaleva, M. V. Gorev, V. S. Bondarev [et al.] // J. Non-Cryst. Solids. - 2022. - Vol. 597. - Ст. 121935, DOI 10.1016/j.jnoncrysol.2022.121935. - Cited References: 29. - The authors are grateful to Dr. Ewa Rysiakiewicz-Pasek (Wroclaw University of Science and Technology, Poland) for the preparation and characterization of borosilicate glasses. X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS” . - ISSN 0022-3093
Кл.слова (ненормированные):
Nanocomposite -- Ferroelectrics -- Phase transition -- Thermal expansion -- Entropy
Аннотация: The thermal properties of nanocomposites obtained by incorporating a ferroelectric (NH4)2SO4 (AS) into porous glasses (PG) was studied for the first time. X-ray diffraction studies showed a strong increase in the ratio of the size of nanocrystallites grown in glass matrices to pore size, dcryst/ dpore = 0.47→1.50→5.00, with a decrease in dpore = 320→46→7 nm. Calorimetric and dilatometric measurements showed a change from a first-order phase transition in AS single crystal to a second-order transformation in AS nanocrystallites. A restricted geometry also led to a significant decrease in the anomalous entropy in AS+PG samples compared to AS (J/mol∙K): 17.7 (AS)→12.4 (AS+PG320)→10.4 (AS+PG46)→8.1 (AS+PG7). A discussion of the nontrivial behavior of the phase transition temperature in embedded AS was carried out using the degree of PG filling, the ratio dcryst/dpore, texture, and the volumetric and linear baric coefficients for the bulk AS.

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Держатели документа:
Federal Research Center KSC SB RAS, Kirensky Institute of Physics, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Federal Research Center "Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk, 660036, Russian Federation
Ioffe Physico-Technical Institute, RAS, St.-Petersburg, 194021, Russian Federation

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Bondarev, V. S.; Бондарев, Виталий Сергеевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Zaitsev, A. I.; Зайцев, Александр Иванович; Nemtsev, I. V.; Fokin, A. V.; Flerov, I. N.; Флёров, Игорь Николаевич
}
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Comparative analysis of elastocaloric and barocaloric effects in single-crystal and ceramic ferroelectric (NH4)2SO4 / E. Mikhaleva, M. Gorev, V. Bondarev [et al.] // Scripta Mater. - 2021. - Vol. 191. - P. 149-154, DOI 10.1016/j.scriptamat.2020.09.030. - Cited References: 47. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023 ). X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS” . - ISSN 1359-6462
Кл.слова (ненормированные):
Polymorphic phase transformation -- Phase diagram -- Order–disorder phenomena -- Entropy -- Caloric effects
Аннотация: We report the influence of anisotropy and texture on elasto(ElCE)- and baro(BCE)-caloric effects in single-crystal and ceramic (NH4)2SO4. Inverse extensive and intensive ElCE in ceramics, (ΔSElCE)cer = 87 J/kg·K; ΔTAD = - 11.6 K), as well as in a single crystal along the ferroelectric axis a, (ΔSElCE)a = 115 J/kg·K; (ΔTAD)a = - 16 K, significantly exceed BCE, ΔSBCE = 75 J/kg·K; ΔTAD = - 9.8 K, even at low pressure ~ 0.3 GPa. Caloric parameters of ammonium sulphate are comparable with those for promising solid-state refrigerants.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Bondarev, V. S.; Бондарев, Виталий Сергеевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Flerov, I. N.; Флёров, Игорь Николаевич
}
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    Investigation of thermal properties and structure of complex fluoride K3ZrF7 / M. V. Gorev, M. S. Molokeev, A. V. Kartashev [et al.] // J. Fluor. Chem. - 2021. - Vol. 241. - Ст. 109677, DOI 10.1016/j.jfluchem.2020.109677. - Cited References: 44. - The reported study was funded by RFBR according to the research project No. 18-02-00269 a. X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS" . - ISSN 0022-1139
   Перевод заглавия: Исследование теплофизических свойств и структуры комплексного фторида K3ZrF7
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Structure -- Heat capacity -- Entropy -- Thermal expansion
Аннотация: X-ray, calorimetric and dilatometric studies of K3ZrF7 revealed the existence of the phase transition Fm-3m ↔ R-3m at T0 = 320 K. The structural model assumes a disorder of a pentagonal bipyramid ZrF7 with the following ratio of equivalent orientation positions in the initial and distorted phases: 12 to 6. A good agreement was found between the experimental and model-calculated changes in strain and entropy during the phase transition. A comparative analysis of entropy and structural parameters of related fluorides K3ZrF7 - (NH4)2KZrF7 - (NH4)3ZrF7 was performed. The anomalous behavior of thermodynamic properties in the range 140−230 K is not typical for phase transitions and is accompanied by a significant change in the entropy of the crystal lattice.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Institute of Chemistry, Far Eastern Department of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Pogoreltsev, E. I.; Погорельцев, Евгений Ильич; Mel'nikova, S. V.; Мельникова, Светлана Владимировна; Laptash, N. M.; Flerov, I. N.; Флёров, Игорь Николаевич
}
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10.

    Phase transition in RbCdZrF7: Structure and thermal properties / E. V. Bogdanov, M. S. Molokeev, M. V. Gorev [et al.] // J. Fluor. Chem. - 2021. - Vol. 245. - Ст. 109748, DOI 10.1016/j.jfluchem.2021.109748. - Cited References: 30. - The reported study was funded by RFBR according to the research project No. 18-02-00269 a. X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS" . - ISSN 0022-1139
   Перевод заглавия: Фазовый переход в RbCdZrF7: структура и термические свойства
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Structure -- Heat capacity -- Entropy -- Thermal expansion
Аннотация: X-ray, calorimetric and dilatometric studies of RbCdZrF7 revealed the existence of the second order phase transition Cmcm - P21/m at T0 = 200 K. The structure of the initial and distorted phases is ordered. The phase transition is associated with displacements of fluorine atoms, which leads to minor rotations of the CdF7 and ZrF7 pentagonal bipyramids. A small change in entropy, 0.1R, is characteristic of displacive-type transformations. An anomalously high susceptibility of the transition temperature to hydrostatic pressure was found.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Institute of Chemistry, Far Eastern Branch of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Bogdanov, E. V.; Богданов, Евгений Витальевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Gorev, M. V.; Горев, Михаил Васильевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Laptash, N. M.; Flerov, I. N.; Флёров, Игорь Николаевич
}
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11.

Calorimetric, dilatometric and DTA under pressure studies of the phase transitions in elpasolite (NH4)2KZrF7 / M. V. Gorev, A. V. Kartashev, E. V. Bogdanov [et al.] // J. Fluor. Chem. - 2020. - Vol. 235. - Ст. 109523, DOI 10.1016/j.jfluchem.2020.109523. - Cited References: 45. - The reported study was funded by RFBR according to the research project No. 18-02-00269 a. X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS" . - ISSN 0022-1139
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Heat capacity -- Entropy -- Thermal expansion -- High pressure
Аннотация: Heat capacity, thermal expansion, and sensitivity to the hydrostatic pressure of (NH4)2KZrF7 elpasolite are studied in a wide temperature range. The changes in deformation and entropy during successive phase transitions are determined: Δ(ΔV/V) = 3·10−4; ΔS = 8 J/mol K The temperatures and entropies of phase transitions turned out to be slightly sensitive to pressure changes. An analysis of the entropy of phase transformations was performed in the framework of the model of the cubic phase structure Fm-3 m. In the low temperature phase, an anomalous behavior of thermodynamic properties, which is not characteristic of phase transitions, was observed, accompanied by a significant change in the crystal lattice entropy.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, 660049, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation
Institute of Chemistry, Far Eastern Department of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Flerov, I. N.; Флёров, Игорь Николаевич; Laptash, N. M.
}
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12.

Features of the behavior of the barocaloric effect near ferroelectric phase transition close to the tricritical point / E. A. Mikhaleva, I. N. Flerov, M. V. Gorev [et al.] // Crystals. - 2020. - Vol. 10, Is. 1. - Ст. 51, DOI 10.3390/cryst10010051. - Cited References: 28. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023) . - ISSN 2073-4352
Кл.слова (ненормированные):
polymorphic phase transformation -- phase diagram -- order-disorder phenomena -- entropy -- barocaloric effect
Аннотация: A detailed study of the effect of temperature and pressure on heat capacity, entropy and hysteresis phenomena near the ferroelectric phase transition in ammonium sulfate (AS) was performed. An analysis of experimental results within the framework of the phenomenological theory showed that taking into account the temperature-dependent part of the anomalous entropy leads to a significant increase in the barocaloric effect (BCE). The maximum values of extensive and intensive BCE near the tricritical point are outstanding: ΔSmaxBCE≈85 J/kgK, ΔTmaxAD≈12 K and can be achieved at low pressure ∼0.5 GPa.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russia
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, 660074 Krasnoyarsk, Russia
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, 660049 Krasnoyarsk, Russia

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Flerov, I. N.; Флёров, Игорь Николаевич; Gorev, M. V.; Горев, Михаил Васильевич; Bondarev, I. A.; Бондарев, Илья Александрович; Bogdanov, E. V.; Богданов, Евгений Витальевич
}
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13.

Flerov, I. N.
The role of chemical pressure in the formation of the piezocaloric effect in fluorine–oxygen ferroics / I. Flerov, M. Gorev // Ferroelectrics. - 2020. - Vol. 567, Is. 1 : Special Issue in Honor of Professor Stanislav A. Grindev on the Occasion of His 83rd Birthday. - P. 1-12, DOI 10.1080/00150193.2020.1791581. - Cited References: 25 . - ISSN 0015-0193
Кл.слова (ненормированные):
Fluorides -- phase transitions -- entropy -- high pressure -- caloric effect
Аннотация: We performed an analysis of the phase diagrams and piezocaloric properties of fluorine–oxygen ferroics (NH4)2MeOxF6-x (Me: W, Mo, Nb; x: 1, 2) with orthorhombic symmetry. The nature of the influence of chemical pressure on the caloric efficiency has been elucidated. Substitutions of central atoms, Mo → W and Nb → W, lead to an increase in absolute and integral piezocaloric effects.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Флёров, Игорь Николаевич
}
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14.

Anisotropy of piezocaloric effect at ferroelectric phase transitions in ammonium hydrogen sulphate / E. A. Mikhaleva, M. V. Gorev, M. S. Molokeev [et al.] // J. Alloys Compd. - 2020. - Vol. 839. - Ст. 155085, DOI 10.1016/j.jallcom.2020.155085. - Cited References: 31. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023 ). X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS" . - ISSN 0925-8388
Кл.слова (ненормированные):
Piezocaloric effect -- Phase transition -- Ferroelectrics -- Thermal expansion -- High-pressure -- Entropy
Аннотация: The role of anisotropy of the thermal expansion in formation of piezocaloric effect (PCE) near ferroelectric phase transitions in NH4HSO4 was studied. Strong difference in linear baric coefficients and as a result in intensive and extensive PCE associated with the different crystallographic axes was found. PCE giving the main contribution to the barocaloric effect were determined at both phase transitions. Rather strong effect of the lattice dilatation on the tuning of PCE was observed. Comparative analysis of PCE at the phase transitions in different materials showed that NH4HSO4 can be considered as a promising solid-state refrigerant. A hypothetical cooling cycle based on alternate using uniaxial pressure along two axes was considered.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Department of Physics, Far Eastern State Transport University, Khabarovsk, 680021, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Flerov, I. N.; Флёров, Игорь Николаевич
}
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15.

Optical and calorimetric studies of K2TaF7 / S. V. Mel'nikova [et al.] // J. Fluor. Chem. - 2019. - Vol. 222-223. - P. 75-80, DOI 10.1016/j.jfluchem.2019.04.016. - Cited References: 26. - The reported study was funded by RFBR according to the research project № 18-02-00269. . - ISSN 0022-1139
Кл.слова (ненормированные):
Phase transition -- Ferroelasticity -- Optical properties -- Photoelasticity -- Heat capacity -- Entropy
Аннотация: Optical and calorimetric experiments on K2TaF7 are performed in a wide temperature range. No features were found in the behavior of the birefringence Δnb(T), the angle of rotation of the indicatrix ϕ(T) and the heat capacity ΔCp(T) except for those associated with the Pnma↔P21/c phase transition. Structural transformation was characterized as strong first order “proper” ferroelastic accompanied by a huge angle ϕ ≈40° and strong pre-transition phenomena in Δnb(T). Two contributions to the anomalies of the optical properties were found associated with the photoelastic effect and the transition parameter related linearly to the spontaneous deformation. Thermal treatments cause correlated changes in temperature and enthalpy of the phase transition, which leads to the invariance of the large magnitude of the corresponding entropy ΔS = 22 J/mol·K which does not match the model with the absence of structural disorder in the Pnma phase.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Department of Physics, Far Eastern State Transport University, Khabarovsk, 680021, Russian Federation
Institute of Chemistry, Far Eastern Department of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Mel'nikova, S. V.; Мельникова, Светлана Владимировна; Bogdanov, E. V.; Богданов, Евгений Витальевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Laptash, N. M.; Flerov, I. N.; Флёров, Игорь Николаевич
}
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16.

    Structural, thermal and optical properties of elpasolite-like (NH4)2KZrF7 / E. I. Pogoreltsev [et al.] // J. Solid State Chem. - 2019. - Vol. 277. - P. 376-380, DOI 10.1016/j.jssc.2019.06.013. - Cited References: 28. - The reported study was funded by RFBR according to the research project No. 18-02-00269 a . The authors are grateful to Krasnoyarsk Center of collective use of SB RAS for providing X-ray analytical equipment. . - ISSN 0022-4596
   Перевод заглавия: Структурные, термические и оптические свойства эльпасолитоподобного кристалла (NH4)2KZrF7
Кл.слова (ненормированные):
Phase transition -- Structure -- Optical properties -- Heat capacity -- Entropy
Аннотация: New fluoride compound (NH4)2KZrF7 with the elpasolite structure (sp. gr. Fm-3m) was synthesized by partial cationic substitution in (NH4)3ZrF7 cryolite. Due to small difference in ionic radii of K+ and NH4+, non-equivalent crystallographic positions 8c and 4b are occupied by both cations. Investigations of thermal, optical and structural properties in a wide range of temperature revealed two phase transitions Fm-3m ↔ P42/ncm ↔ P42/nmc of the first order. The results obtained are discussed in comparison with the data for the previously studied related cryolite (NH4)3ZrF7.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Far Eastern State Transport University, Khabarovsk, 680021, Russian Federation
Institute of Chemistry, Far Eastern Branch of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Pogoreltsev, E. I.; Погорельцев, Евгений Ильич; Mel'nikova, S. V.; Мельникова, Светлана Владимировна; Molokeev, M. S.; Молокеев, Максим Сергеевич; Flerov, I. N.; Флёров, Игорь Николаевич; Laptash, N. M.
}
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17.

Conventional and inverse barocaloric effects in ferroelectric NH4HSO4 / M. V. Gorev [et al.] // J. Alloys Compd. - 2019. - Vol. 806. - P. 1047-1051, DOI 10.1016/j.jallcom.2019.07.273. - Cited References: 22 . - ISSN 0925-8388
Кл.слова (ненормированные):
Polymorphic phase transformation -- Phase diagram -- Order–disorder phenomena -- Entropy -- Barocaloric effect
Аннотация: In this study, the conventional and inverse barocaloric effects (BCE) in ferroelectric NH4HSO4 are reported. Maximum extensive and intensive BCE near order–disorder phase transition can be achieved at low pressure p≤0.1 GPa. Large thermal expansion of the crystal lattice plays a very important role in the developing conventional BCE and conversation between BCE of different sign in the narrow temperature range.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Flerov, I. N.; Флёров, Игорь Николаевич; Bogdanov, E. V.; Богданов, Евгений Витальевич
}
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18.

Heat capacity, thermal expansion and sensitivity to hydrostatic pressure of (NH 4 ) 3 SiF 7 at successive structural phase transitions / E. V. Bogdanov [et al.] // J. Solid State Chem. - 2019. - Vol. 276. - P. 152-158, DOI 10.1016/j.jssc.2019.04.029. - Cited References: 20 . - ISSN 0022-4596
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Heat capacity -- Entropy -- Thermal expansion -- High pressure
Аннотация: Heat capacity, thermal dilatation, permittivity and sensitivity to external pressure of (NH4)3SiF 7 were studied. Due to the absence of cubic phases Pm3¯m and Pa3¯, a strong decrease in the total entropy change ∑ΔSi =19 J/mol K associated with four successive transformations P4/mbm↔Pbam↔P2 1 /c11↔P1¯↔P12 1 /c1 was found in silicate in comparison with other double fluoride salts (NH4)3MeF7 (Me: Ge, Ti, Sn) Using analysis of the excess heat capacity in the framework of the thermodynamic theory, the entropies associated with each individual phase transition were determined. In accordance with the entropic parameters, the complete ordering of the structural elements occurs in the monoclinic phase P21/c11. Further change in symmetry is associated with small entropy changes which prove insignificant displacement of structural units. A T−p phase diagram was constructed and good agreement was found between measured and calculated baric coefficients. © 2019 Elsevier Inc.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, 660049, Russian Federation
Institute of Chemistry, Far Eastern Department of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Bogdanov, E. V.; Богданов, Евгений Витальевич; Pogoreltsev, E. I.; Погорельцев, Евгений Ильич; Gorev, M. V.; Горев, Михаил Васильевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Laptash, N. M.; Flerov, I. N.; Флеров, Игорь Николаевич
}
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19.

Zinenko, V. I.
Thermodynamics of spin ice in staggered and direct (along the [111] axis) fields in the cluster approximation / V. I. Zinenko, M. S. Pavlovskii // J. Exp. Theor. Phys. - 2017. - Vol. 124, Is. 2. - P. 295-303, DOI 10.1134/S1063776117020182. - Cited References:15. - This work was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, and the Krasnoyarsk Territory Foundation for Supporting the Scientific and Research Activity (project no. 16-42-243039). . - ISSN 1063-7761. - ISSN 1090-6509

РУБ Physics, Multidisciplinary
Рубрики:
ENTROPY
HEAT
Аннотация: We have analyzed the low-temperature thermodynamic properties of spin ice in the staggered and direct (acting along the [111] axis) fields for rare-earth oxides with the chalcolamprite structure and general formula Re23+Me24+O72- . Calculations have been performed in the cluster approximation. The results have been compared with experimental temperature dependences of heat capacity and entropy for Dy2Ti2O7 compound for different values of the external field in the [111] direction. The experimental data and calculated results have also been compared for the Pr2Ru2O7 compound with the antiferromagnetic ordering of magnetic moments of ruthenium ions, which gives rise to the staggered field acting on the system of rare-earth ions. The calculated temperature dependences of heat capacity and entropy are in good agreement with experimental data.

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Публикация на русском языке Зиненко, Виктор Иванович. Термодинамика спинового льда в «шатающемся» и прямом в направлении [111] полях в приближении кластеров [Текст] / В. И. Зиненко, М. С. Павловский // Журн. эксперим. и теор. физ. : Наука, 2017. - Т. 151 Вып. 2. - С. 346–355

Доп.точки доступа:
Pavlovskii, M. S.; Павловский, Максим Сергеевич; Зиненко, Виктор Иванович; Russian Foundation for Basic Research; Government of the Krasnoyarsk Territory; Krasnoyarsk Territory Foundation for Supporting the Scientific and Research Activity [16-42-243039]
}
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20.

    Thermal, dielectric and barocaloric properties of NH4HSO4 crystallized from an aqueous solution and the melt / E. A. Mikhaleva [et al.] // Solid State Sci. - 2017. - Vol. 67. - P. 1-7, DOI 10.1016/j.solidstatesciences.2017.03.004. - Cited References: 27. - We are grateful to T.N. Davydova for the preparation of the sample from an aqueous solution and Dr. M.S. Molokeev for X-ray characterization of the samples. The study was partially supported by the Russian Foundation for Basic Research, research project No. 16-32-00092 mol_а. . - ISSN 1293-2558
   Перевод заглавия: Термические, диэлектрические и барокалорические свойства NH4HSO4 кристаллизованного из водного раствора и расплава
Кл.слова (ненормированные):
Entropy -- Ferroelectric -- Phase diagram -- Phase transition -- Thermal and dielectric properties
Аннотация: A study of heat capacity, thermal dilatation, permittivity, dielectric loops and susceptibility to hydrostatic pressure was carried out on quasi-ceramic samples of NH4HSO4 obtained from an aqueous solution as well as the melt. The main parameters of the successive P21/c (T1) ↔ Pc (T2) ↔ P1 phase transitions did not depend on the method of preparation of the samples, and were close to those determined in previous studies of single crystal and powder, except for the sign and magnitude of the baric coefficient for T2. Direct measurements of the pressure effect on the permittivity and thermal properties showed dT2/dp = −123 K·GPa−1, which is consistent in terms of magnitude and sign with the baric coefficient evaluated using dilatometric and calorimetric data in the framework of the Clausius-Clapeyron equation. Thus, the temperature region of the ferroelectric Pc phase existence is extended under pressure. A strong decrease in the entropy jump at the Pc ↔ P1 transformation with an increase in pressure, and the linear dependence of T2 on pressure, indicate that an increase in pressure shifts this phase transition towards the tricritical point on the T–p phase diagram. A significant barocaloric effect was found in the region of the Pc ↔ P1 phase transition.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Centre, KSC SB RAS, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, Russian Federation
Krasnoyarsk State Agrarian University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Flerov, I. N.; Флёров, Игорь Николаевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Gorev, M. V.; Горев, Михаил Васильевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Bondarev, V. S.; Бондарев, Виталий Сергеевич
}
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