Библиотека института физики им. Л.В. Киренского СО РАН

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Каталог книг и брошюр библиотеки ИФ СО РАН

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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuz'menko A. M., Mukhin A. A., Ivanov V. Y., Kadomtseva A. M., Lebedev S. P., Bezmaternykh L. N.
Заглавие : Antiferromagnetic Resonance and Dielectric Properties of Rare-earth Ferroborates in the Submillimeter Frequency Range
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 113, Is. 1. - P113-120. - ISSN 1063-7761, DOI 10.1134/S106377611105013X
Примечания : Cited References: 27. - This work was supported by the Russian Foundation for Basic Research, project no. 10-02-00846.
Предметные рубрики: GDFE3(BO3)(4)
SPECTROSCOPY
CRYSTAL
Ключевые слова (''Своб.индексиров.''): antiferromagnetic resonance--basic parameters--effective anisotropy constant--ferroborates--ferroics--ferromagnetic orderings--frequency ranges--magnetic interactions--magnetoresonance--millimeter frequency range--rare earth ions--submillimeters--antiferromagnetic materials--crystallography--erbium--europium--ferromagnetic resonance--ion exchange--magnetic anisotropy--magnetic devices--magnetic structure--permittivity--resonance--antiferromagnetism
Аннотация: The magnetoresonance and dielectric properties of a number of crystals of a new family of multiferroics, namely, rare-earth ferroborates RFe(3)(BO(3))(4) (R = Y, Eu, Pr, Tb, Tb(0.25)Er(0.75)), are studied in the submillimeter frequency range (nu = 3-20 cm(-1)). Ferroborates with R = Y, Tb, and Eu exhibit permittivity jumps at temperatures of 375, 198, and 58 K, respectively, which are caused by the R32 - P3(1)2(1) phase transition. Antiferromagnetic resonance (AFMR) modes in the subsystem of Fe(3+) ions are detected in the range of antiferromagnetic ordering (T T(N)
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yang, Zhiyu, Liu, Gaochao, Zhao, Yifei, Zhou, Yayun, Qiao, Jianwei, Molokeev M. S., Swart, Hendrik C., Xia, Zhiguo
Заглавие : Competitive site occupation toward improved quantum efficiency of SrLaScO4:Eu red phosphors for warm white LEDs
Коллективы : International Cooperation Project of National Key Research and Development Program of China [2021YFE0105700]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [51972118, 51961145101]; Guangzhou Science & Technology Project [202007020005]; State Key Laboratory of Luminescent Materials and Devices [Skllmd-2021-09]; China Postdoctoral Science FoundationChina Postdoctoral Science Foundation [2021M691053]; Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program [2017BT01X137]; RFBRRussian Foundation for Basic Research (RFBR) [19-52-80003]; NRF International: SA/China Joint Research Programme 2021 [CHIN2002265 06921 UID 132785]
Место публикации : Adv. Opt. Mater. - 2022. - Vol. 10. Is. 6. - Ст.2102373. - ISSN 2195-1071, DOI 10.1002/adom.202102373
Примечания : Cited References: 42. - This research was supported by the International Cooperation Project of National Key Research and Development Program of China (Program No. 2021YFE0105700), National Natural Science Foundation of China (Grant Nos. 51972118 and 51961145101), Guangzhou Science & Technology Project (Project No. 202007020005), the State Key Laboratory of Luminescent Materials and Devices (Grant No. Skllmd-2021-09), China Postdoctoral Science Foundation (Grant No. 2021M691053), and the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (Program No. 2017BT01X137). This work was also funded by RFBR according to the research Project No. 19-52-80003 and the NRF International: SA/China Joint Research Programme 2021 - CHIN2002265 06921 UID 132785
Предметные рубрики: LUMINESCENCE
EUROPIUM
BLUE
EU2+
STABILIZATION
EPR
Аннотация: The discovery of Eu2+-doped high-efficiency red phosphors remains a vital challenge for white light-emitting diode (WLED) applications. It is therefore urgent to find effective strategies managing the oxidation state to help reduce Eu3+ to Eu2+ and accordingly increase the photoluminescence quantum yield (PLQY). Herein, a new red-emitting SrLaScO4:Eu phosphor is designed, and the PLQY is enhanced from 13% to 67% under 450 nm excitation by employing (NH4)2SO4-assisted sintering. Combined structural analysis, optical spectroscopy, and theoretical calculation reveal that predominant Eu2+ prefers to occupy the Sr2+ sites in the SrLaScO4 enabling red emission, and a competitive site occupation of Eu3+ in La3+ can be restrained, and the reduction mechanism of Eu3+ to Eu2+ originating from the (NH4)2SO4 addition is analyzed. The fabricated WLED device using red-emitting SrLaScO4:Eu and yellow-emitting Y3(Al,Ga)5O12:Ce3+ exhibits a high color-rendering index of 86.7 at a low correlated color temperature of 4005 K. This work provides a feasible reduction strategy for guiding the development of high-efficiency Eu2+-doped red phosphor for WLED applications.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisenko Y. G., Sedykh A. E., Molokeev M. S., Oreshonkov A. S., Aleksandrovsky A. S., Krylov A. S., Khritokhin N. A., Sal'nikova E. I., Andreev O. V., Muller-Buschbaum K.
Заглавие : Crystal and electronic structure, thermochemical and photophysical properties of europium-silver sulfate monohydrate AgEu(SO4)2·H2O
Место публикации : J. Solid State Chem. - 2021. - Vol. 294. - Ст.121898. - ISSN 00224596 (ISSN), DOI 10.1016/j.jssc.2020.121898
Примечания : Cited References: 54. - This work was partially supported by the Russian Foundation for Basic Research (Grant 19-33-90258∖19 ). Use of equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center « Krasnoyarsk Science Center SB RAS» is acknowledged
Аннотация: In order to synthesize single crystals of europium-silver double sulfate monohydrate, a hydrothermal reaction route was used. It was found that the crystallization cannot be performed under standard conditions. The compound AgEu(SO4)2·H2O crystallizes in the trigonal crystal system, space group P3221 (a = 6.917(1), c = 12.996(2) Å, V = 538.53(17) Å3). The structure consists of triple-capped trigonal prisms [EuO9], in which one oxygen atom belongs to crystalline water, silver octahedra [AgO6], and sulfate tetrahedra [SO4]. The hydrogen bonds in the system additionally stabilize the structure. The electronic band structure wasstudied by density functional theory calculations which show that AgEu(SO4)2·H2O is an indirect band gap dielectric. Temperature dependent photoluminescence spectroscopy shows emission bands of transitions from the 5D0 state to the spin-orbit components of the 7FJmultiplet (J = 0–6).The ultranarrow transition 5D0 - 7F0 shows a red shift with respect to other europium-containing water-free sulfates that is ascribed to the presence of OH group in the crystal structure in the close vicinity of the Eu3+ ion. An effect of abnormal sensitivity of the Ω4 intensity factor to minor distortions of the local environment is detected for the observed low local symmetry of C2.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisova L. T., Molokeev M. S., Irtyugo L. A., Belousova N. V., Denisov V. M.
Заглавие : Crystal structure and thermodynamic properties of germanate CuEu2Ge2O8
Место публикации : Phys. Solid State. - 2022. - Vol. 64, Is. 12. - P.2045-2048. - ISSN 10637834 (ISSN), DOI 10.21883/PSS.2022.12.54406.460. - ISSN 10906460 (eISSN)
Примечания : Cited References: 18. - The work has been partially funded within the framework of the state science assignment of Federal State Independent Institution for Higher Education ”Siberian Federal University“, project number FSRZ-2020-0013
Аннотация: Copper-europium germanate CuEu2Ge2O8 was obtained from the initial CuO, Eu2O3 and GeO2 oxides using solid-phase synthesis by annealing in air in the temperature range of 1223-1273 K. Its crystal structure was determined (space group Cm). The influence of temperature on high-temperature heat capacity of the synthesized germanate was studied by the differential scanning calorimetry method. It was found that the dependence of heat capacity on temperature has an extreme value related to a phase transition. The thermodynamic properties were calculated based on the experimental data about heat capacity.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisova L. T., Molokeev M. S., Aleksandrovskii A. S., Kargin Y. F., Golubeva E. O., Denisov V. M.
Заглавие : Crystal structure, luminescence, and thermodynamic properties of Pb10–xEux(GeO4)2+x(VO4)4–x (x = 0.1, 0.2, 0.3) substituted apatites
Место публикации : Inorg. Mater. - 2021. - Vol. 57, Is. 11. - P.1158-1166. - ISSN 00201685 (ISSN), DOI 10.1134/S0020168521110030
Примечания : Cited References: 26. - This work was supported in part by the Russian Federation Ministry of Science and Higher Education as part of the state research target for the Siberian Federal University federal state autonomous educational institution of higher education, project no. FSRZ-2020-0013
Аннотация: Pb10 – xEux(GeO4)2 + x(VO4)4 – x (x = 0.1, 0.2, 0.3) Eu-substituted lead germanatovanadates with the apatite structure have been prepared by solid-state reactions, via firing in air in the temperature range 773–1073 K, using oxides (PbO, Eu2O3, GeO2, and V2O5) as starting materials. Using X-ray diffraction, we have determined the hexagonal cell parameters (sp. gr. P63/m) of the synthesized phases and refined their crystal structure (the atomic position coordinates, isotropic thermal parameters, and principal bond lengths in their structure are presented). We have measured the luminescence spectra of the Pb10 – xEux(GeO4)2 + x(VO4)4 – x (x = 0.1, 0.2, 0.3) apatites and shown that europium concentration has little effect on the shape of the luminescence spectra. Using experimental heat capacity data obtained for polycrystalline samples by differential scanning calorimetry in the temperature range 350–1050 K, we calculated the main thermodynamic functions of the Eu-substituted lead germanatovanadates.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ruseikina A. V., Solovyov L. A., Molokeev M. S., Andreev O. V.
Заглавие : Crystal structures of EuLnCuS3 (Ln = Nd and Sm)
Место публикации : Russ. J. Inorg. Chem.: MAIK Nauka-Interperiodica / Springer, 2012. - Vol. 57, Is. 1. - P.79-83. - ISSN 0036-0236, DOI 10.1134/S0036023612010172
Примечания : This work was supported by the Federal Target Program "Scientific and Pedagogical Personnel of Innovative Russia" for 2009-2013 (grant nos. 6K/143-09 (P 646) and NK-409/5 (P2263)) and the President of the Russian Federation (Support Program for Leading Scientific Schools of the Russian Federation, grant NSh-4645.2010.2).The results of this study have been presented at the X International Scientific Conference “Solid-State Chemistry: Nanomaterials, Nanotechnologies” (Stavropol, October 17–22, 2010) and the All-Russia Scientific Conference “Challenges of Modern Chemistry. Theory and Practice” (Ufa, October 21–23, 2010).
Предметные рубрики: RARE-EARTH
MAGNETIC-PROPERTIES
COPPER SULFIDE
CHALCOGENIDES
EUROPIUM
EU2CUS3
Аннотация: The compound sulfides EuLnCuS3 (Ln = Nd and Sm) were obtained for the first time. Their crystal structures were determined from X-ray powder diffraction data. The crystals of both compounds are orthorhombic (space group Pnma). The compound EuNdCuS3 is isostructural with BaLaCuS3; the unit cell parameters are a = 11.0438(2) Å, b = 4.0660(1) Å, c = 11.4149(4) Å. The compound EuSmCuS3 is isostructural with Eu2CuS3; the unit cell parameters are a = 10.4202(2) Å, b = 3.9701(1) Å, c = 12.8022(2) Å.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisenko Y. G., Sedykh A. E., Oreshonkov A. S., Molokeev M. S., Azarapin N. O., Sal'nikova E. I., Chimitova O. D., Andreev O. V., Razumkova I. A., Muller-Buschbaum K.
Заглавие : Europium (II) sulfate EuSO4: Synthesis methods, crystal and electronic structure, luminescence properties
Коллективы : [0273-2021-0008]
Место публикации : Eur. J. Inorg. Chem. - 2022. - Vol. 2022, Is. 12. - Ст.e202200043. - ISSN 1434-1948, DOI 10.1002/ejic.202200043. - ISSN 1099-0682(eISSN)
Примечания : Cited References: 69. - This research is partially supported by the state order of BINM SB RAS (project no. 0273-2021-0008)
Предметные рубрики: DEPENDENT DECAY BEHAVIOR
ELECTROCHEMICAL REDUCTION
OPTICAL-PROPERTIES
Аннотация: In the present work, we report on the synthesis of EuSO4 powders by two different methods using EuS as starting material. The compound EuSO4 contains divalent europium and crystallizes in the orthorhombic crystal system, space group Pnma with parameters close to SrSO4. The compound exhibits near isotropic thermal expansion over the temperature range 300–700 K. EuSO4 was examined by Raman, Fourier-transform infrared absorption and luminescence spectroscopy methods. EuSO4 is found to be an indirect bandgap material with a bandgap close to direct electronic transition. The emission lifetime of divalent europium d-f emission in EuSO4 shows an unusual behavior for stoichiometric compounds, as it shortens upon cooling from 1.11(1) μs at room temperature to 0.44(1) μs at 77 K.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisenko Y. G., Aleksandrovsky A. S., Atuchin V. V., Krylov A. S., Molokeev M. S., Oreshonkov A. S., Shestakov N. P., Andreev O. V.
Заглавие : Exploration of structural, thermal and spectroscopic properties of self-activated sulfate Eu2(SO4)3 with isolated SO4 groups
Место публикации : J. Ind. Eng. Chem. - 2018. - Vol. 68. - P.109-116. - ISSN 1226086X (ISSN), DOI 10.1016/j.jiec.2018.07.034
Примечания : Cited References: 83. - This work was supported by the Russian Foundation for Basic Research ( 16-52-48010 , 17-52-53031 ). The equipments of the Collective Use Center — Kirensky Institute of Physics, Federal Research Center KSC Siberian Branch Russian Academy of Sciences [ http://ccu.kirensky.ru/ ] was used.
Ключевые слова (''Своб.индексиров.''): europium sulfate--synthesis--structure--thermal analysis--photoluminescence
Аннотация: Eu2(SO4)3 was synthesized by chemical precipitation method and the crystal structure was determined by Rietveld analysis. The compound crystallizes in monoclinic space group С2/с. In the air environment, Eu2(SO4)3 is stable up to 670 °C. The sample of Eu2(SO4)3 was examined by Raman, Fourier-transform infrared absorption and luminescence spectroscopy methods. The low site symmetry of SO4 tetrahedra results in the appearance of the IR inactive ν1 mode around 1000 cm−1 and ν2 modes below 500 cm−1. The band intensities redistribution in the luminescent spectra of Eu3+ ions is analyzed in terms of the peculiarities of its local environment.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Aleksandrovsky A. S., Bazarov B. G., Bazarova J. G., Chimitova, Olga D., Denisenko, Yuriy G., Gavrilova T. A., Krylov A. S., Maximovskiy, Eugene A., Molokeev M. S., Oreshonkov A. S., Pugachev, Alexey M., Surovtsev, Nikolay V.
Заглавие : Exploration of structural, vibrational and spectroscopic properties of self-activated orthorhombic double molybdate RbEu(MoO4)2 with isolated MoO4 units
Коллективы : RFBR [16-52-48010, 17-52-53031, 18-03-00557]; Ministry of Science and Higher Education of the Russian Federation [0339-2016-0007]; Act 211 Government of the Russian Federation [02.A03.21.0011]; Ministry of Education and Science of the Russian Federation [4.1346.2017/4.6]
Место публикации : J. Alloy. Compd. - 2019. - Vol. 785. - P.692-697. - ISSN 0925-8388, DOI 10.1016/j.jallcom.2019.01.013. - ISSN 1873-4669(eISSN)
Примечания : Cited References: 42. - The reported study was funded by RFBR according to research projects 16-52-48010, 17-52-53031 and 18-03-00557. Besides, this study was supported by the Ministry of Science and Higher Education of the Russian Federation (project 0339-2016-0007). The work was supported by Act 211 Government of the Russian Federation, contract No 02.A03.21.0011. Additionally, the work was partially supported by the Ministry of Education and Science of the Russian Federation (4.1346.2017/4.6).
Предметные рубрики: MORPHOLOGY-CONTROLLED SYNTHESIS
LUMINESCENCE PROPERTIES
Ключевые слова (''Своб.индексиров.''): rubidium europium molybdate--solid state reaction--rietveld refinement--dsc--raman luminescence
Аннотация: RbEu(MoO4)2 is synthesized by the two-step solid state reaction method. The crystal structure of RbEu(MoO4)2 is defined by Rietveld analysis in space group Pbcn with cell parameters a = 5.13502(5), b = 18.8581(2) and c = 8.12849(7) Å, V = 787.13(1) Å3, Z = 4 (RB = 0.86%). This molybdate possesses its phase transition at 817 K and melts at 1250 K. The Raman spectra were measured with the excitation at λ = 1064 and 514.5 nm. The photoluminescence spectrum is evaluated under the excitation at 514.5 nm. The absolute domination of hypersensitive 5D0→7F2 transition is observed. The ultranarrow 5D0→7F0 transition in RbEu(MoO4)2 is positioned at 580.2 nm being 0.2 nm blue shifted, with respect to that in Eu2(MoO4)3.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S., Vereshchagin S. N.
Заглавие : Crystal structure and some properties of europium(III) Catena-{tris(1,3-diethyl-2-thiobarbiturate)}
Место публикации : J. Struct. Chem.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 57, Is. 1. - P.167-174. - ISSN 00224766 (ISSN), DOI 10.1134/S0022476616010200
Примечания : Cited References: 25. - The work was supported within the State Contract of the Ministry of Education and Science of the Russian Federation for research in the Siberian Federal University in 2015.
Предметные рубрики: 1,3-diethyl-2-thiobarbituric acid
Hydrogen-bond
Diffraction
Series
Ключевые слова (''Своб.индексиров.''): crystal structure--complex--europium(iii)--1,3-diethyl-2-thiobarbituric acid--thermal analysis--ir spectroscopy--photoluminescence
Аннотация: The [Eu(HDTBA)3] n complex (I), HDTBA is 1,3-diethyl-2-thiobarbituric acid (C8H12N2O2S) is synthesized and its structure is determined by X-ray crystallography. The crystals of I are triclinic: a = 11.0205(2) Å, b = 11.8811(3) Å, c = 12.7312(2) Å, α = 100.933(1)°, β = 109.704(1)°, γ = 101.161(1)°, V = 1479.88(5) Å3, space group P-1, Z = 2. Each of three independent DETBA- ions is a bridging μ2-O,O′-coordinated ligand. The coordination polyhedron of Eu(III) is a distorted octahedron. Bridging DETBA- organize the octahedra into an infinite two-dimensional layer. The structure contains intramolecular hydrogen bonds but intermolecular hydrogen bonds and the π-π interaction are absent. The results of IR spectroscopy and photoluminescence agree with the single crystal X-ray diffraction data. The main product of the thermal decomposition of I at 900°C is oxysulfate Eu2O2SO4. © 2016 Pleiades Publishing, Ltd.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kartashev A. V., Flerov I. N., Volkov N. V., Sablina K. A.
Заглавие : Heat capacity and magnetocaloric effect in manganites (La1-yEuy)(0.7)Pb0.3MnO3 (y:0.2; 0.6)
Место публикации : J. Magn. Magn. Mater. - 2010. - Vol. 322, Is. 6. - P.622-627. - MAR. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2009.10.026
Примечания : Cited Reference Count: 17. - Гранты: This work was supported by the Krasnoyarsk's regional sciences foundation and RFBR in the framework of project "Siberia''(Grant no. 09-02-98001), by Integrational project of Siberian and Far Eastern Departments of RAS(no. 101) and by Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools(Projectno. NSh-1011.2008.2). Dr Maxim S. Molokeev is acknowledged for the X-raycharacterization of the samples.Финансирующая организация: Krasnoyarsk's regional sciences foundation [09-02-98001]; Siberian and Far Eastern Departments [101]; Russian Federation [NSh-1011.2008.2]
Предметные рубрики:
Ключевые слова (''Своб.индексиров.''): manganites--magnetic phase transition--heat capacity--magnetocaloric effect--heat capacity--magnetic phase transition--magnetocaloric effect--manganites--adiabatic calorimeters--heat capacities--magnetic phase transitions--magneto-caloric effects--magnetocaloric effect--multi-element--nonmagnetics--relative cooling power--temperature range--europium--lead--manganese compounds--oxide minerals--specific heat--phase transitions
Аннотация: Heat capacity and intensive magnetocaloric effect (MCE) in manganites (La1-yEuy)(0.7)Pb0.3MnO3[y=0.2; 0.6] (LEPM) were investigated by means of adiabatic calorimeter. The heat capacity anomaly as well as the values of both the intensive (Delta T-AD) and the extensive (Delta S-MCE) MCE were found to decrease upon increased replacement of La with nonmagnetic Eu. However, because of widening of the MCE peaks, the LEPM compounds show the relative cooling power, RCP/Delta H, comparable to other solid solutions of manganites. Owing to strong effect of Eu - La substitution on the Curie temperature, LEPM might have potential as the solid state refrigerants in multi-element cooling apparatus operating in a wide temperature range. (C) 2009 Elsevier B.V. All rights reserved.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisenko Y. G., Molokeev M. S., Krylov A. S., Aleksandrovsky A. S., Oreshonkov A. S., Atuchin V. V., Azarapin N. O., Plyusnin P. E., Sal'nikova E. I., Andreev O. V.
Заглавие : High-temperature oxidation of europium (II) sulfide
Место публикации : J. Ind. Eng. Chem. - 2019. - Vol. 79. - P.62-70. - ISSN 1226086X (ISSN) , DOI 10.1016/j.jiec.2019.05.006
Примечания : Cited References: 68. - The authors are grateful for the support from RFBR ( 18-02-00754 , 18-08-00985 , and 18-32-20011 ). This study was also supported by the Russian Science Foundation (project 19-42-02003 , in part of conceptualization).
Аннотация: The process of high-temperature oxidation of EuS in the air was explored in the temperature range of 500–1000 °C. The oxidation reaction enthalpy was determined (ΔH0exp = −1718.5 kJ/mol). The study of oxidation products allowed to establish the mechanism of EuS oxidation with oxygen. At 500–600 °C, EuS is oxidized to a mixture of Eu3+-containing compounds (Eu3S4, Eu2O2S). In the range of 700–1000 °C, only europium oxysulfate Eu2O2SO4 is formed. The structure refinement for Eu2O2SO4 was performed by the Rietveld method. The luminescence intensity of europium oxysulfate Eu2O2SO4 with characteristic 4f-4f transitions from the 5D0 state was investigated as a function of oxidation temperature.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaykhutdinov K. A., Popkov S. I., Semenov S. V., Balaev D. A., Dubrovskiy A. A., Sablina K. A., Sapronova N. V., Volkov N. V.
Заглавие : Low-temperature resistance and magnetoresistance hysteresis in polycrystalline (La0.5Eu0.5)(0.7)Pb0.3MnO3
Разночтения заглавия :авие SCOPUS: Low-temperature resistance and magnetoresistance hysteresis in polycrystalline (La0.5Eu0.5)0.7Pb 0.3MnO3
Место публикации : J. Appl. Phys.: AMER INST PHYSICS, 2011. - Vol. 109, Is. 5. - Ст.53711. - ISSN 0021-8979, DOI 10.1063/1.3559303
Примечания : Cited References: 20. - This study was partially supported by the Russian Foundation for Basic Research, Project No. 08-02-00259a and the Lavrentyev Competition of the Young Scientists' Projects of the Siberian Branch of the Russian Academy of Sciences, Project No. 12.
Предметные рубрики: RESISTIVITY MINIMUM
MANGANITES
FILMS
Ключевые слова (''Своб.индексиров.''): antiferromagnets--electrical resistances--ferromagnets--field dependence--inter-grain--lanthanum manganites--low temperatures--low-temperature resistance--polycrystalline--temperature dependence--tunnel contacts--antiferromagnetic materials--europium--ferromagnetic materials--ferromagnetism--hysteresis--lead--magnetic field effects--magnetoelectronics--magnetoresistance--magnets--manganese oxide--paramagnetism--superconducting materials--electric resistance
Аннотация: The behavior of temperature dependences of electrical resistance and magnetoresistance of polycrystalline substituted lanthanum manganite (La0.5Eu0.5)(0.7)Pb0.3MnO3 at low temperatures was thoroughly studied. A broad hysteresis was found in the field dependences of electrical resistance in the low-temperature region. Above 40 K, no hysteresis feature was observed. The temperature T = 40 K corresponds to the temperature of minimum electrical resistance and the temperature T-N to the antiferromagnet-paramagnet phase transition of the material of the intergrain boundaries. In this work we propose a model which explains the observed features of the rho(T) and rho(H) curves at temperatures below T-N by the formation of a network of ferromagnet-antiferromagnet-ferromagnet tunnel contacts. (C) 2011 American Institute of Physics. [doi:10.1063/1.3559303]
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaikhutdinov K. A., Popkov S. I., Semenov S. V., Balaev D. A., Dubrovskiy A. A., Sablina K. A., Volkov N. V.
Заглавие : Low-temperature resistivity of polycrystalline (La0.5Eu 0.5)0.7Pb0.3MnO3 in a magnetic fields
Место публикации : J. Phys. Conf. Ser. - 2010. - Vol. 200, Is. SECTION 5. - ISSN 17426588 (ISSN) , DOI 10.1088/1742-6596/200/5/052025
Ключевые слова (''Своб.индексиров.''): antiferromagnetic grains--comparative analysis--ferromagnetic grain--low temperatures--polycrystalline--specific heat measurement--spin dependent tunneling--transport and magnetic properties--antiferromagnetism--electric resistance--europium--grain boundaries--grain size and shape--lanthanum compounds--lead--magnetic field effects--magnetic properties--magnetoresistance--manganese oxide--single crystals--thermal variables measurement--lanthanum
Аннотация: The effect of grain boundaries on magnetoresistance (MR) of manganites have been investigated by the comparative analysis of the properties of single-crystal and polycrystalline (La0.5Eu0.5) 0.7Pb0.3MnO3. While MR of the single crystal is maximum near the Curie temperature and vanishes in the low-temperature region, the polycrystalline (La0.5Eu0.5)0.7Pb 0.3MnO3 sample exhibits high MR in the low-temperature region. In order to clarify the origin of the low-temperature MR, the transport and magnetic properties of the polycrystalline (La0.5Eu 0.5)0.7Pb0.3MnO3 in magnetic fields have been supplemented by study of magnetic properties and specific heat measurements. The results obtained could be attributed to spin-dependent tunneling between ferromagnetic grains through insulating antiferromagnetic grain boundaries. © 2010 IOP Publishing Ltd.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Dyakonov V. P., Szymczak R., Prokhorov A. D., Zubov E., Prokhorov A. A., Petrakovskii G. A., Bezmaternykh L. N., Berkowski M., Varyukhin V., Szymczak H.
Заглавие : Magnetic and EPR studies of the EuFe3(BO3)(4) single crystal
Коллективы :
Разночтения заглавия :авие SCOPUS: Magnetic and EPR studies of the EuFe 3(BO 3) 4 single crystal
Место публикации : Eur. Phys. J. B: SPRINGER, 2010. - Vol. 78, Is. 3. - P291-298. - ISSN 1434-6028, DOI 10.1140/epjb/e2010-10059-3
Примечания : Cited References: 23. - A.A. Prokhorov is grateful to Mianowski Fund for financial support.
Предметные рубрики: EARTH
GDFE3(BO3)(4)
MULTIFERROICS
Ключевые слова (''Своб.индексиров.''): absorption lines--antiferromagnetic orderings--applied magnetic fields--basal planes--easy direction of magnetizations--electron paramagnetic resonance--epr measurements--epr spectra--epr studies--europium ions--exchange fields--g factors--lorentz--magnetic measurements--magnetic subsystems--orientation dependence--sub-lattices--temperature dependence--temperature range--trigonal symmetry--zeeman effect--antiferromagnetism--crystal orientation--europium--magnetic fields--magnetic moments--magnetic variables measurement--magnetization--paramagnetic resonance--paramagnetism--single crystals--spectroscopy--electron spin resonance spectroscopy
Аннотация: Magnetic and electron paramagnetic resonance (EPR) properties of EuFe3(BO3)(4) single crystals have been studied over the temperature range of 300-4.2 K and in a magnetic field up to 5 T. The temperature, field and orientation dependences of susceptibility, magnetization and EPR spectra are presented. An antiferromagnetic ordering of the Fe subsystem occurs at about 37 K. The easy direction of magnetization perpendicular to the c axis is determined by magnetic measurements. Below 10 K, we observe an increase of susceptibility connected with the polarization of the Eu sublattice by an effective exchange field of the ordered Fe magnetic subsystem. In a magnetic field perpendicular to the c axis, we have observed an increase of magnetization at T 10 K in the applied magnetic field, which can be attributed to the appearance of the magnetic moment induced by the magnetic field applied in the basal plane. According to EPR measurements, the distance between the maximum and minimum of derivative of absorption line of the Lorentz type is equal to 319 Gs. The anisotropy of g-factor and linewidth is due to the influence of crystalline field of trigonal symmetry. The peculiarities of temperature dependence of both intensity and linewidth are caused by the influence of excited states of europium ion (Eu3+). It is supposed that the difference between the g-factors from EPR and the magnetic measurements is caused by exchange interaction between rare earth and Fe subsystems via anomalous Zeeman effect.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhang M., Xia Z., Molokeev M. S., Shi L., Liu Q.
Заглавие : New insight into the crystal structure of Sr4Ca(PO4)2SiO4 and the photoluminescence tuning of Sr4Ca(PO4)2SiO4:Ce3+,Na+,Eu2+ phosphors
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 38. - P.9078-9084. - ISSN 20507534 (ISSN), DOI 10.1039/c6tc03373c
Примечания : Cited References: 31
Ключевые слова (''Своб.индексиров.''): calcium--energy transfer--europium--light emission--light emitting diodes--luminescence--phosphate minerals--phosphors--photoluminescence--positive ions--rietveld refinement--tuning--chemical compositions--energy transfer mechanisms--green component--hexagonal cells--luminescence properties--single phase--solid state method--white lightemitting diodes (wleds)--crystal structure
Аннотация: A new single phase based on the substitution of a Sr cation by a Ca cation in the apatite-type Sr5(PO4)2(SiO4) has been fabricated with the nominal chemical composition of Sr4Ca(PO4)2(SiO4), which appears as a definite compound rather than a solid solution between (Sr,Ca)3(PO4)2 and (Sr,Ca)2SiO4. The crystal structure of Sr4Ca(PO4)2(SiO4) has been firstly analysed by the difference electron map, and further resolved by the Rietveld refinement, and the final composition has been determined as Sr4Ca(PO4)(2+x)(SiO4)(1-x)(OH)x (x = 0.64) with a hexagonal cell (P63/m). The Ce3+/Eu2+ codoped Sr4Ca(PO4)2SiO4 phosphors have been designed and prepared by the solid state method, and the photoluminescence tuning from blue to green upon 365 nm ultraviolet (UV) radiation can be realized, which is ascribed to the energy transfer from Ce3+ to Eu2+ ions. The luminescence properties and the energy transfer mechanism in Ce3+/Eu2+ codoped Sr4Ca(PO4)2SiO4 phosphors have been discussed, which might act as potential candidates for blue-green components in UV-pumped white light emitting diodes (WLEDs). © 2016 The Royal Society of Chemistry.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H. P., Huang Z. H., Xia Z. G., Molokeev M. S., Atuchin V. V., Fang M. H., Huang S. F.
Заглавие : New yellow-emitting whitlockite-type structure Sr1.75Ca 1.25(PO4)2:Eu2+ phosphor for near-UV pumped white light-emitting devices
Место публикации : Inorg. Chem.: American Chemical Society, 2014. - Vol. 53, Is. 10. - P.5129-5135. - ISSN 0020-1669, DOI 10.1021/ic500230v. - ISSN 1520-510X
Примечания : Cited References: 31. - This work was supported by the National Natural Science Foundations of China (Grant Nos. 51032007, 51002146, 51272242), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130022110006), and the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950). V.V.A. gratefully acknowledges the Ministry of Education and Science of the Russian Federation for the financial support. S.H. would like to acknowledge the China Scholarship Council (CSC) for providing a doctoral scholarship for his Ph.D. study at the University of Auckland.
Предметные рубрики: LUMINESCENCE PROPERTIES
CRYSTAL-STRUCTURE
RED PHOSPHOR
DIODES
LEDS
SR
CA
ORTHOPHOSPHATE
CA-3(PO4)2
EUROPIUM
Аннотация: New compound discovery is of interest in the field of inorganic solid-state chemistry. In this work, a whitlockite-type structure Sr1.75Ca1.25(PO4)2 newly found by composition design in the Sr3(PO4)2–Ca3(PO4)2 join was reported. Crystal structure and luminescence properties of Sr1.75Ca1.25(PO4)2:Eu2+ were investigated, and the yellow-emitting phosphor was further employed in fabricating near-ultraviolet-pumped white light-emitting diodes (w-LEDs). The structure and crystallographic site occupancy of Eu2+ in the host were identified via X-ray powder diffraction refinement using Rietveld method. The Sr1.75Ca1.25(PO4)2:Eu2+ phosphors absorb in the UV–vis spectral region of 250–430 nm and exhibit an intense asymmetric broadband emission peaking at 518 nm under λex = 365 nm which is ascribed to the 5d–4f allowed transition of Eu2+. The luminescence properties and mechanism are also investigated as a function of Eu2+ concentration. A white LED device which is obtained by combining a 370 nm UV chip with commercial blue phosphor and the present yellow phosphor has been fabricated and exhibit good application properties.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaykhutdinov K. A., Popkov S. I., Balaev D. A., Semenov S. V., Bykov A. A., Dubrovskiy A. A., Sapronova N. V., Volkov N. V.
Заглавие : Non-linear current-voltage characteristics of (La0.5Eu0.5)(0.7)Pb0.3MnO3 single crystals: Possible manifestation of the internal heating of charge carriers
Коллективы :
Разночтения заглавия :авие SCOPUS: Non-linear currentvoltage characteristics of (La0.5Eu 0.5)0.7Pb0.3MnO3 single crystals: Possible manifestation of the internal heating of chargecarriers
Место публикации : Physica B: ELSEVIER SCIENCE BV, 2010. - Vol. 405, Is. 24. - P4961-4965. - ISSN 0921-4526, DOI 10.1016/j.physb.2010.09.043
Примечания : Cited References: 19. - The authors are grateful to A.N. Lavrov for useful discussions on the results. This study was partially supported by the Russian Foundation for Basic Research, Project no. 08-02-00259a and the Lavrent'ev Young Scientists' Competition of the Siberian Branch of the Russian Academy of Sciences. Project no. 12.
Предметные рубрики: INSULATOR-METAL TRANSITION
PR0.7CA0.3MNO3
MANGANITES
Ключевые слова (''Своб.индексиров.''): manganites--negative differential resistance--cvc--cvc--manganites--negative differential resistance--applied electric field--charge ordering--current switching--cvc--dielectric regions--experimental data--internal heating--lanthanum manganites--metal-dielectric transition--negative differential resistances--non equilibrium--non-linear--sample heating--temperature evolution--transport currents--electric fields--electron gas--europium--heating--lanthanum--lead--manganites--negative resistance--phase separation--single crystals--thermal conductivity--manganese oxide
Аннотация: Temperature evolution of the current-voltage characteristics (CVCs) of a single-crystal lanthanum manganite (La0.5Eu0.5)(0.7)Pb0.3MnO3 is investigated in a wide (up to 1 A) range of instrumental currents. Effects of a transport current and an applied electric field on the resistance of the material are studied in view of possible implementation of the charge ordering break in dielectric regions occurring due to phase separation in manganites. A negative differential resistance portion observed in the CVCs suggests the presence of a current switching effect. Below the temperature of the metal-dielectric transition in (La0.5Eu0.5)(0.7)Pb0.3MnO3, the hysteresis is observed in the CVC. The detailed analysis of the internal sample heating on the basis of experimental data on thermal conductivity showed, however, that these CVC features can be explained within the concept of non-equilibrium heating of electron gas. (C) 2010 Elsevier B.V. All rights reserved.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Hu T., Gao Y., Molokeev M. S., Xia Z., Zhang Q.
Заглавие : Non-stoichiometry in Ca2Al2SiO7 enabling mixed-valent europium toward ratiometric temperature sensing
Место публикации : Sci. China Mater. - 2019. - Vol. 62, Is. 12. - P.1807–1814. - ISSN 20958226 (ISSN), DOI 10.1007/s40843-019-1202-x
Примечания : Cited References: 53. - This work was supported by the National Natural Science Foundation of China (51722202, 51972118 and 51572023), the Guangdong Provincial Science & Technology Project (2018A050506004), and Innovation Projects of Department of Education of Guangdong Province (2018KQNCX265).
Аннотация: Eu2+/Eu3+ mixed-valence couple co-doped material holds great potential for ratiometric temperature sensing owing to its different electronic configurations and electron-lattice interaction. Here, the correlation of nonstoichiometry in chemical composition, phase structures and luminescence propertis of Ca2Al2Si1−xO7:Eu is discussed, and controlled Eu2+/Eu3+ valence and tunable emission appear with decreasing Si content. It is found that the 2Ca2+ + Si4+ ↔ Eu2+ + Eu3+ + Al3+ cosubstitution accounts for the structural stability and charge balance mechanism. Benefiting from the diverse thermal dependent emission behaviors of Eu2+ and Eu3+, Ca2Al2Si1−xO7:Eu thermometer exhibits excellent temperature sensing performances with the maximum absolute and relative sensitivity being 0.024 K−1 (at 303 K) and 2.46% K−1 (at 443 K) and good signal discriminability. We propose that the emission quenching of Eu2+ is ascribed to 5d electrons depopulation through Eu2+/Eu3+ intervalence charge transfer state, while the quenching of Eu3+ comes from multi phonon relaxation. Our work demonstrates the potential of Ca2Al2Si1−xO7:Eu for noncontact optical thermometry, and also highlights mixed valence europium containing com pounds toward temperature sensing.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volkov N. V., Petrakovskii G. A., Vasiliev V. N., Velikanov D. A., Sablina K. A., Patrin K. G.
Заглавие : Observation of mixed two-phase state in Eu0.7Pb0.3MnO3 single crystal by magnetic resonance method
Место публикации : Physica B. - 2002. - Vol. 324, Is. 1-4. - P.254-260. - ISSN 0921-4526, DOI 10.1016/S0921-4526(02)01397-2
Примечания : Cited References: 19
Предметные рубрики: OPTIMALLY DOPED MANGANITES
COLOSSAL MAGNETORESISTANCE
PARAMAGNETIC ANOMALIES
CURIE-TEMPERATURE
LA1-XCAXMNO3
RELAXATION
SEPARATION
Ключевые слова (''Своб.индексиров.''): manganites--cmr--magnetic resonance--phase separation--cmr--magnetic resonance--manganites--phase separation--europium compounds--ferromagnetic materials--paramagnetic resonance--phase separation--phase transitions--manganites--single crystals
Аннотация: The magnetic resonance measurements show that the mixed two-phase state takes place in the Eu0.7Pb0.3MnO3 single crystal. The coexistence of the magnetic phases is observed in vicinity of the magnetic phase transition, where the sample exhibits the effect of the CMR. The frequency-field dependencies of the spectra allow to conclude that these phases are paramagnetic and ferromagnetic ones. Moreover, the study of the frequency dependencies shows the sensitivity of the mixed-phase state to the external magnetic field. This suggests that the scenario of the phase separation is realized in this case and the mixed two-phase state is not related to simple chemical inhomogeneity. (C) 2002 Elsevier Science B.V. All rights reserved.
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