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1.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Aleksandrov K. S., Sorokin B. P., Turchin P. P., Burkov S. I., Glushkov D. A., Karpovich A. A.
Заглавие : Effects of static electric field and of mechanical pressure on surface acoustic waves propagation in La3Ga5SiO14 piezoelectric single crystals
Коллективы : IEEE International Ultrasonics Symposium
Место публикации : Proc IEEE Ultrason Symp. - 1995. - Vol. 1. - P.409-412. - ISBN 1051-0117
Ключевые слова (''Своб.индексиров.''): electric field effects--electrostriction--lanthanum compounds--piezoelectric materials--piezoelectricity--pressure effects--quartz--single crystals--tensors--bulk acoustic wave--dielectric permeability--electromechanical bond coefficients--lanthanum gallium silicide--mechanical pressure--nonlinear electromechanical properties--nonlinear piezoelectric effect--piezoquartz--static electric field--tensorial components--ultrasonic propagation
Аннотация: The complete set of tensorial components of linear and nonlinear electromechanical properties for La3Ga5SiO14 piezoelectric crystals have been obtained. These data were used for the analysis of influence of static electrical field and of uniaxial homogeneous mechanical pressure on the propagation of surface acoustic waves.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrakovskii G. A., Aleksandrov K. S., Aplesnin S. S., Roessli B., Semadeni F., Amato A., Baines C., Bartolome J., Evangelisti M.
Заглавие : Spin-glass state in CuGa2O4
Место публикации : Phys. Rev. B. - 2001. - Vol. 63, Is. 18. - Ст.184425. - ISSN 0163-1829, DOI 10.1103/PhysRevB.63.184425
Примечания : Cited References: 28
Предметные рубрики: TRANSITION
Ключевые слова (''Своб.индексиров.''): copper--gallium--glass--oxygen--acceleration--article--magnetism--measurement--molecular dynamics--phase transition
Аннотация: Magnetic susceptibility, magnetization, specific-heat, and positive muon spin relaxation (?SR) measurements have been used to characterize the magnetic ground state of the spinel compound CuGa2O4. We observe a spin-glass transition of the S = 1/2 Cu2+ spins below Tf = 2.5 K characterized by a cusp in the susceptibility curve which is suppressed when a magnetic field is applied. We show that the magnetization of CuGa2O4 depends on the magnetic history of the sample. Well below Tf, the muon signal resembles the dynamical Kubo-Toyabe expression reflecting that the spin freezing process in CuGa2O4 results in a Gaussian distribution of the magnetic moments. By means of Monte Carlo simulations, we obtain the relevant exchange integrals between the Cu2+ spins in this compound.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kaminskii A. A., Butashin A. V., Aleksandrov K. S., Bezmaternykh L. N., Temerov V. L., Kravtsov N. V., Firsov V. V., Seo D. T., Hommerich U., Temple D., Braud A.
Заглавие : Gd3Ga5O12:Nd3+ crystals for a continuous-wave diode-pumped laser operating in 4F3/2 4I11/2 and 4F3/2 4I13/2 channels
Место публикации : Crystallogr. Rep. - 2002. - Vol. 47, Is. 2. - P.308-312. - ISSN 1063-7745, DOI 10.1134/1.1466508
Примечания : Cited References: 15
Предметные рубрики: GALLIUM GARNET
EMISSION
Ключевые слова (''Своб.индексиров.''): gadolinium--gallium--neodymium--article--concentration response--crystal--pump--spectroscopy--x ray--x ray topography
Аннотация: Garnet crystals of the composition Gd3Ga5O12:Nd3+ (concentration series CNd = 1-10 at. %) were grown from flux. In terms of spectroscopy, these crystals, unlike those grown from melts, form a medium with a single activator center. For the first time, continuous-wave lasing was excited by diode pumping with the use of Gd3Ga5O12:Nd3+ crystals at the wavelengths ?3 = 1.3315 and ?4 = 1.3370 ?m of the 4F3/2 4I13/2 channel and also the simultaneous generation at two wavelengths, ?1 = 1.0621 and ?2 = 1.0600 ?m, of the 4F3/2 4I11/2 channel. В© 2002 MAIK "Nauka/Interperiodica".
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Valiev U. V., Gruber J. B., Sardar D. K., Zandi B., Kachur I. S., Mukhammadiev A. K., Piryatinskaya V. G., Sokolov V. Y., Edelman I. S.
Заглавие : Zeeman effect and stark splitting of the electronic states of the rare-earth ion in the paramagnetic terbium garnets Tb3Ga5O12 and Tb3Al5O12
Разночтения заглавия :авие SCOPUS: Zeeman effect and stark splitting of the electronic states of the rare-earth ion in the paramagnetic terbium garnets Tb3Ga 5O12 and Tb3Al5O12
Место публикации : Phys. Solid State. - 2007. - Vol. 49, Is. 1. - P.91-98. - ISSN 1063-7834, DOI 10.1134/S1063783407010167
Примечания : Cited References: 14
Предметные рубрики: YTTRIUM-ALUMINUM-GARNET
SELECTIVE POLARIZED SPECTROSCOPY
CRYSTAL-FIELD ANALYSIS
GALLIUM GARNET
Аннотация: The Zeeman effect in the F-7(6) - D-5(4) absorption band of the Tb3+ ion in the paramagnetic garnets Tb3Ga5O12 and Tb3Al5O12 was Studied. The field dependences of the Zeeman splitting of some absorption lines arc found to exhibit unusual behavior: as the magnetic field increases, the hand splitting decreases rather than increases. Symmetry analysis relates these lines to 4f - 4f electron transitions of the doublet-quasi-doublet or quasi-doublet-doublet type, for which the field dependences of the splitting differ radically from the well-known field dependences of the Zeeman splitting for quasi-doublet-quasi-doublet or quasi-doublet-singlet transitions in a longitudinal magnetic field.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sorokin P. B., Ovchinnikov S. G., Avramov P. V., Chernozatonskii L.A., Fedorov D.G.
Заглавие : Atypical quantum confinement effect in silicon nanowires
Место публикации : J. Phys. Chem. A. - WASHINGTON: AMER CHEMICAL SOC, 2008. - Vol. 112, Is. 40. - С. 9955-9964. - OCT 9. - ISSN 1089-5639, DOI 10.1021/jp805069b
Примечания : Cited Reference Count: 25. - Гранты: This work was in part partially supported by a CREST (Core Research for Evolutional Science and Technology) grant in the Area of High Performance Computing for Multiscale and Multiphysics Phenomena from the Japan Science and Technology Agency (JST) as well as by Russian Fund of Basic Researches (grant 08-02-01096) (L.A.C.). P.V.A. acknowledges the encouragement of Dr. Keiji Morokuma, Research Leader at Fukui Institute for Fundamental Chemistry. The geometry of all presented structures was visualized by ChemCraft software.SUP25/SUP L.A.C. acknowledges I. V. Stankevich for help and fruitful discussions. P.B.S. is grateful to the Joint Supercomputer Center of the Russian Academy of Sciences for access to a cluster computer for quantum-chemical calculations.Финансирующая организация: Japan Science and Technology Agency (JST); Russian Fund of Basic Researches [08-02-01096]
Предметные рубрики: ELECTRONIC-STRUCTURE
OPTICAL-PROPERTIES
SI
DENSITY
WIRES
EXCHANGE
ATOMS
DOTS
Ключевые слова (''Своб.индексиров.''): electric wire--energy gap--gallium alloys--mathematical models--nanostructured materials--nanostructures--nanowires--quantum confinement--quantum electronics--semiconductor quantum dots--silicon--ami methods--band gaps--blue shifts--dinger equations--linear junctions--monotonic decreases--quantum confinement effects--quantum dots--semiempirical--silicon nanowires--system sizes--theoretical models--nanocrystalline silicon--nanowire--quantum dot--silicon--article--chemistry--electron--quantum theory--electrons--nanowires--quantum dots--quantum theory--silicon
Аннотация: The quantum confinement effect (QCE) of linear junctions of silicon icosahedral quantum dots (IQD) and pentagonal nanowires (PNW) was studied using DFT and semiempirical AM1 methods. The formation of complex IQD/PNW structures leads to the localization of the HOMO and LUMO on different parts of the system and to a pronounced blue shift of the band gap; the typical QCE with a monotonic decrease of the band gap upon the system size breaks down. A simple one-electron one-dimensional Schrodinger equation model is proposed for the description and explanation of the unconventional quantum confinement behavior of silicon IQD/PNW systems. On the basis of the theoretical models, the experimentally discovered deviations from the typical QCE for nanocrystalline silicon are explained.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aleksandrovsky A.S., Bezmaternykh L.N., Bovina A.F., Gudim I.A., Kharlamova S.A., Krylov A.S., Melnikova S.V., Temerov V.Ye.
Заглавие : Unusual Valence States of Manganese Ions in Gadolinium Gallium Aluminum Borate Single Crystals
Место публикации : Известия высших учебных заведений. Физика. - 2008. - Т. 51, № 10/2. - С. 115-119
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7.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Gunyakov V. A., Zyryanov V. Ya., Myslivets S. A., Arkhipkin V. G., Shabanov V. F.
Заглавие : Electrically controllable optical switch based on one-dimensional photonic crystal
Коллективы : International Conference on Advanced Optoelectronics and Lasers
Место публикации : Proceedings of CAOL 2008: 4th International Conference on Advanced Optoelectronics and Lasers. - 2008. - 4th International Conference on Advanced Optoelectronics and Lasers, CAOL 2008 (29 September 2008 through 4 October 2008, Alushta, Crimea, ) Conference code: 74830. - С. 186-188. - ISBN 9781424419746 (ISBN), DOI 10.1109/CAOL.2008.4671886
Ключевые слова (''Своб.индексиров.''): detect mode--liquid crystal--photonic band gap--photonic crystal--crossed polarizers--detect mode--electric-field--electrooptical switches--light waves--spectral ranges--crystal atomic structure--crystal defects--energy gap--gallium alloys--light sources--liquid crystals--liquid lasers--nematic liquid crystals--optical devices--photonic crystals--photonic band gap
Аннотация: Electrooptical switch within narrow spectral range has been demonstrated. The switch consisting of one-dimensional photonic crystal with a nematic liquid crystal defect layer was placed between two crossed polarizers. Principle of operation is based on the interference of the ordinary and extraordinary light waves passed across the device due to the electric-field induced coincidence of their wavelengths. © 2008 IEEE.
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8.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Arkhipkin V. G., Gunyakov V. A., Myslivets S. A., Zyryanov V. Ya., Shabanov V. F.
Заглавие : Defect modes in real photonic crystals
Коллективы : International Conference on Advanced Optoelectronics and Lasers
Место публикации : Proceedings of CAOL 2008: 4th International Conference on Advanced Optoelectronics and Lasers. - 2008. - 4th International Conference on Advanced Optoelectronics and Lasers, CAOL 2008 (29 September 2008 through 4 October 2008, Alushta, Crimea, ) Conference code: 74830. - С. 183-185. - ISBN 9781424419746 (ISBN), DOI 10.1109/CAOL.2008.4671857
Ключевые слова (''Своб.индексиров.''): detect mode--liquid crystal--photonic band gap--photonic crystal--defect modes--detect mode--number of layers--photonic crystal structures--crystal atomic structure--crystal structure--defects--energy gap--gallium alloys--light sources--liquid crystals--liquid lasers--optical devices--photonic band gap--silicon on insulator technology--photonic crystals
Аннотация: It is demonstrated experimentally that amplitudes of defect modes of one-dimensional photonic crystal have maximal value near edges of the photonic band gap while at the centre of the stop-band they are reduced, moreover than more number of layers in photonic crystal, the less the amplitude of defect mode at the center of the PBG. We explain such behavior of defect modes presence of losses at propagation of light in real photonic crystal structures. © 2008 IEEE.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aleksandrovsky A. S., Arkhipkin V. G., Bezmaternykh L. N., Gudim I. A., Krylov A. S., Vagizov F.
Заглавие : Origin of color centers in the flux-grown europium gallium garnet
Место публикации : J. Appl. Phys.: AMER INST PHYSICS, 2008. - Vol. 103, Is. 8. - Ст.83102. - ISSN 0021-8979, DOI 10.1063/1.2902365
Примечания : Cited References: 7
Предметные рубрики: SPECTRA
IONS
Ключевые слова (''Своб.индексиров.''): absorption--europium alloys--garnets--ultraviolet radiation--calcium-free flux--flux-grown europium gallium garnet--color centers
Аннотация: Europium gallium garnet (EuGG) single crystals were grown from fluxes with various contents. Optical absorption spectra of EuGG grown from a flux containing calcium show an additional band in the ultraviolet and blue regions of the spectra as compared to the case of a calcium-free flux. Mossbauer spectra of the samples grown from the fluxes with different additives show no signs of other valence states of the europium ions except for 3+. However, they indicate changes in the crystal field due to the entrance of additive ions. The nature of the additional absorption must be the same as that for calcium-doped gadolinium gallium garnet, i.e., anion vacancies. Mossbauer isotope shifts and quadrupole splitting for EuGG are determined. (C) 2008 American Institute of Physics.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Mankov Y. I., Tsikalov D. S.
Заглавие : High-Frequency Susceptibility of a Superlattice with 2D Inhomogeneities
Коллективы :
Разночтения заглавия :авие SCOPUS: High-frequency susceptibility of a superlattice with 2D inhomogeneities
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2008. - Vol. 107, Is. 4. - P603-611. - ISSN 1063-7761, DOI 10.1134/S1063776108100075
Примечания : Cited References: 26. - This work was supported in part by grant no. 3818.2008.3 from the President of Russia in accordance with the program supporting leading scientific schools.
Предметные рубрики: SPIN-WAVE SUSCEPTIBILITY
PERIODIC MULTILAYERS
LOCALIZATION
SYSTEMS
SPECTRUM
DISORDER
MEDIA
Ключевые слова (''Своб.индексиров.''): energy conservation--energy gap--energy management--frequency bands--gallium alloys--green's function--probability density function--three dimensional--band gaps--energy conservation laws--green functions--high frequencies--imaginary parts--magnon crystals--scattered waves--superlattice layers--wave spectrums--phase interfaces
Аннотация: We investigate the high-frequency susceptibility (Green function) of an initially sinusoidal 1D superlattice with 2D phase inhomogeneities that model the deformations of the interfaces between the superlattice layers. For waves propagating along the superlattice axis ( the geometry of a photon or magnon crystal), we have found a peculiar behavior of the imaginary part of the Green function that consists in a significant difference between the peaks corresponding to the edges of the band gap in the wave spectrum. The peak corresponding to the lower-frequency band edge remains essentially unchanged as the root-mean-square fluctuation of the 2D inhomogeneities. 2 increases, while the peak corresponding to the higher-frequency band edge broaden and decreases sharply in height until its complete disappearance with increasing gamma(2). This behavior of the peaks corresponds to a band gap closure mechanism that differs from the traditional one characteristic of 1D and 3D inhomogeneities. These effects can be explained by a peculiarity of the energy conservation laws for the incident and scattered waves for 2D inhomogeneities in a 1D superlattice.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aleksandrovsky A.S., Arkhipkin V.G., Bezmaternykh L.N., Gudim I.A., Krylov A.S., Vagizov F.
Заглавие : Optical and Mossbauer Spectroscopy of Europium Gallium Garnet Single Crystals Grown from Fluxes of Different Content
Место публикации : Известия высших учебных заведений. Физика. - 2008. - Т. 51, № 10/2. - С. 110-114
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Chzhan A.V., Vasiliev A. D., Isaeva T. N., Patrin G. S.
Заглавие : Research of features magnetic permeability and domain structures in Fe 2O3:GA crystals near the morin transition
Коллективы : Moscow International Symposium on Magnetism
Место публикации : Solid State Phenomena. - 2009. - Vol. 152-153. - С. 29-32. - ISSN 10120394 (ISSN); 390845168X (ISBN); 9783908451686 (ISBN), DOI 10.4028/www.scientific.net/SSP.152-153.29
Ключевые слова (''Своб.индексиров.''): antiferromagnetic--domain structure--hematite--morin transition--weakly ferromagnetic--antiferromagnetic materials--antiferromagnetism--capillarity--crystal impurities--crystals--ferromagnetic materials--ferromagnetic resonance--ferromagnetism--gallium--hematite--iron ores--magnetic permeability--oxide minerals--permanent magnets--antiferromagnetism--crystal impurities--ferromagnetic materials--ferromagnetism--gallium--hematite--iron compounds--magnetic materials--magnetic permeability--magnetism--afm--antiferromagnetic--antiferromagnetic domains--antiferromagnetics--basal planes--domain configurations--domain structure--morin transitions--multi-layered structure--weakly ferromagnetic--magnetic domains--magnetic domains
Аннотация: Specially picked up web-chamber is used for visualization of domain structure in hematite. An analysis of domain configuration shows, that domain structure of hematite in a basal plane represents multilayered structure which contains domains both in paralleled thickness and in the parallel basal planes. The temperature features of magnetic permeability and domain structures in Fe2O3:Ga crystals near the Morin transition are investigated. Observable changes of magnetic permeability and changes in domain structure confirm that transition from AFM to WFM occurs in the hematite with Ga impurity as transition of the first sort. Results of research of antiferromagnetic and weakly ferromagnetic resonances (AFMR and WFMR) in these compounds are presented.
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13.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Malakhovskii A.V., Sukhachev A.L., Vasil’ev A.D., Leont’ev A.A., Kartashev A.V., Temerov V.L., Gudim I.A.
Заглавие : Influence of partial substitution of iron by gallium on optical properties of GdFe3(bo3)4
Коллективы : "Физика диэлектриков", международная конференция
Место публикации : Физика диэлектриков (Диэлектрики-2011): материалы XII Междунарю конф. - СПб.: Изд-во Российского гос. пед. ун-та им. А. И. Герцена, 2011. - Т. 1. - С. 171-174
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vorotynov A. M., Pankrats A. I., Abramova G. M., Velikanov D. A., Bovina A. F., Sokolov V. V., Filatova I. Y.
Заглавие : Magnetic resonance in a gallium-doped Cu–Cr–S structure
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 58, Is. 4. - P.678-681. - ISSN 10637834 (ISSN), DOI 10.1134/S1063783416040314
Примечания : Cited References: 9
Предметные рубрики: Ferromagnetic spinels
Аннотация: A layered Cu–Cr–S structure doped with Ga ions and consisting of single-crystal CuCrS2 layers, embedded with thin plates of spinel phases CuCr2S4 and CuGaxCr2–xS4, has been studied using the magnetic resonance and magnetic susceptibility methods. The Curie temperature and the saturation magnetization of the spinel phases of the samples have been determined. The spinel phase layer thickness has been estimated. © 2016, Pleiades Publishing, Ltd.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Jiang C., Brik M. G., Li L., Li L., Peng J., Wu J., Molokeev M. S., Wong K. -L., Peng M.
Заглавие : The electronic and optical properties of a narrow-band red-emitting nanophosphor K2NaGaF6:Mn4+ for warm white light-emitting diodes
Место публикации : J. Mater. Chem. C. - 2018. - Vol. 6, Is. 12. - P.3016-3025. - ISSN 20507534 (ISSN), DOI 10.1039/c7tc05098d
Примечания : Cited References: 55. - We acknowledge the financial support received from the Program for Innovative Research Team in University of Ministry of Education of China (Grant No. IRT_17R38), the Key Program of Guangzhou Scientific Research Special Project (Grant No. 201607020009), the National Natural Science Foundation of China (Grant No. 51672085, 51322208, 3160440), and the Fundamental Research Funds for the Central Universities. M. G. Brik acknowledges the supports received from the Recruitment Program of High-end Foreign Experts (Grant No. GDW20145200225), the Programme for the Foreign Experts offered by Chongqing University of Posts and Telecommunications, Ministry of Education and Research of Estonia, (Project PUT430) and European Regional Development Fund (Project TK141), and the Guest Professorship at Kyoto University (Prof. S. Tanabe laboratory). The first-principles calculations were carried out using the resources provided by the Wroclaw centre for Networking and Supercomputing (http://wcss.pl; Grant No. WCSS#10117290).
Ключевые слова (''Своб.индексиров.''): energy efficiency--gallium compounds--light emission--light emitting diodes--manganese--manganese compounds--optical properties--phosphors--precipitation (chemical)--quenching--rietveld refinement--sodium compounds
Аннотация: Recently, as a key red component in the development of warm white light-emitting diodes (WLEDs), Recently, as a key red component in the development of warm white light-emitting diodes (WLEDs), Mn4+-doped fluorides with narrow red emission have sparked rapidly growing interest because they improve color rendition and enhance the visual energy efficiency. Herein, a red nanophosphor, K2NaGaF6:Mn4+, with a diameter of 150-250 nm has been synthesized using a simple co-precipitation method. Rietveld refinement reveals that it crystallizes in the space group Fm3m with the cell parameter a = 8.25320(4) Å. The exchange charge model (ECM) has been used to calculate the energy levels of Mn4+ ions in K2NaGaF6, which match well with the experimental spectra. The as-synthesized phosphor exhibits a narrow red emission at around 630 nm (spin-forbidden 2Eg → 4A2 transition of Mn4+ ions) when excited at 365 nm (4A2g → 4T1g) and 467 nm (4A2g → 4T2g), with a quantum efficiency (QE) of 61% and good resistance to thermal quenching. Based on the structure, the formation mechanism of ZPL has been discussed. In addition, the concentration-dependent decay curves of Mn4+ in K2NaGaF6 were fitted using the Inokuti-Hirayama model, suggesting that the dipole-dipole interactions determine the concentration quenching. Finally, encouraged by the good performance, a warm LED with a CRI of 89.4 and CCT of 3779 K was fabricated by employing the title nanophosphor as the red component. Our findings suggest that K2NaGaF6:Mn4+ can be a viable candidate for the red phosphor used in warm WLEDs.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pavlov E. A., Chuprov I. V., Nikulin M. V., Mal'tsev E. V., Pshenichnaya A. A., Grigoreva T. F., Pastukhov E. A., Skuratov A. P., Lyakhov N. Z.
Заглавие : Mechanochemical synthesis of intermetallic compounds in the gallium-iridium system
Место публикации : Russ. Metall. - 2018. - Is. 8. - P.728-732. - ISSN 0036-0295, DOI 10.1134/S0036029518080141. - ISSN 1555-6255(eISSN)
Примечания : Cited References: 18. - This work was performed in terms of project no. 1622/17 of the Krasnoyarsk Plant of Nonferrous Metals and the Institute of Solid State Chemistry and Mechanochemistry.
Предметные рубрики: ALUMINUM
Ключевые слова (''Своб.индексиров.''): mechanochemical synthesis--intermetallic compounds--gallium--iridium--complex compounds of iridium
Аннотация: The interaction between a solid inert metal (Ir) and an active liquid metal (Ga) during mechanical activation in a high-energy planetary mill is studied by X-ray diffraction and scanning electron microscopy with EDS-apparatus for high-resolution energy dispersive X-ray microanalysis. The influence of mechanical activation conditions on the formation of GaxIry intermetallic compounds and GaxIry/Ir composites and on their solubility in various acids is investigated. Being a surfactant for iridium, gallium propagates along the grain boundaries of polycrystalline iridium particles during mechanical activaiton and, hence, sharply decreases their strength. As a result of strong mechanical deformation during activation, the contact surface area between the solid and liquid metals, where the intermetallic compounds form intensely, increases sharply. As a result of treatment of the products of mechanical activaiton by a mixture of concentrated hydrochloric and nitric acids, iridium (30%) from passes into an acid solution and forms HxIrCly complex compounds, which can interact with bases to form soluble complex salts.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremina R. M., Moshkina E. M., Gavrilova T. P., Gilmutdinov I. F., Sofronova S. N., Kiiamov A. G.
Заглавие : Investigation of the Magnetic Properties of Ludwigites
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2019. - Vol. 83, Is. 7. - P.912-914. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873819070141
Примечания : Cited References: 6. - This work was supported by the Russian Foundation for Basic Research, project no. 17-02-00953.
Аннотация: Single crystals of Cu2AlBO5 and Cu2GaBO5 copper oxyborates are synthesized via solution-melt crystallization and subjected to X-ray diffraction analysis. Parameters of the crystal lattice and the positions of atoms in a unit cell are determined. Copper ions form a structural chain along axis а in Cu2AlBO5 and Cu2GaBO5. Temperature dependences of the magnetic susceptibility are measured. The obtained curves feature kinks at Т = 2.4 (Cu2AlBO5) and 4.1 K (Cu2GaBO5). © 2019, Allerton Press, Inc.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Qiao J., Amachraa M., Molokeev M. S., Chuang Y. -C., Ong S. P., Zhang Q., Xia Z.
Заглавие : Engineering of K3YSi2O7 to Tune Photoluminescence with Selected Activators and Site Occupancy
Место публикации : Chem. Mater. - 2019. - Vol. 31, Is. 18. - P.7770-7778. - ISSN 08974756 (ISSN), DOI 10.1021/acs.chemmater.9b02990
Примечания : Cited References: 48. - This work was supported by the National Natural Science Foundation of China (Nos. 51722202, 51972118 and 51572023), Natural Science Foundations of Beijing (2172036), Fundamental Research Funds for the Central Universities (FRF-TP-18-002C1), and Guangdong Provincial Science & Technology Project (2018A050506004). This work was also supported by the National Science Foundation, Ceramics Program (No. 1911372), and the computational resources were provided by the Extreme Science and Engineering Discovery Environment (XSEDE) supported by the National Science Foundation (No. ACI-1548562).
Аннотация: The luminescence of rare earth ions (Eu2+, Ce3+, and Eu3+)-doped inorganic solids is attractive for the screening of phosphors applied in solid-state lighting and displays and significant to probe the occupied crystallographic sites in the lattice also offering new routes to photoluminescence tuning. Here, we report on the discovery of the Eu- and Ce-activated K3YSi2O7 phosphors. K3YSi2O7:Eu is effectively excited by 450 nm InGaN blue light-emitting diodes (LEDs) and displays an orange-red emission originated from characteristic transitions of both Eu2+ and Eu3+, while K3YSi2O7:Ce3+ shows green emission upon 394 nm near-ultraviolet (NUV) light excitation. Rietveld refinement verifies the successful doping of the activators, and density functional theory (DFT) calculations further support that Eu2+ occupies both K1 and Y2 crystallographic sites, while Ce3+ and Eu3+ only occupy the Y2 site; hence, the broad-band red emission of Eu2+ are attributed to a small DFT band gap (3.69 eV) of K3YSi2O7 host and a selective occupancy of Eu2+ in a highly distorted K1 site and a high crystal field splitting around Y2 sites. The white LEDs device utilizing orange-red-emitting K3YSi2O7:Eu and green-emitting K3YSi2O7:Ce3+ exhibits an excellent CRI of 90.1 at a correlated color temperature of 4523 K. Our work aims at bridging multivalent Eu2+/Eu3+ and Ce3+ site occupancy in the same host to realize photoluminescence tuning and especially exposes new ways to explore new phosphors with multicolor emission pumped by blue and NUV light for white LEDs.
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19.

Вид документа : Статья из журнала
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Автор(ы) : Hu T., Molokeev M. S., Xia Z., Zhang Q.
Заглавие : Aliovalent substitution toward reinforced structural rigidity in Ce3+-doped garnet phosphors featuring improved performance
Место публикации : J. Mater. Chem. C. - 2019. - Vol. 7, Is. 46. - P.14594-14600. - ISSN 20507534 (ISSN), DOI 10.1039/c9tc05354a
Примечания : Cited References: 38. - This work was supported by the National Natural Science Foundation of China (No. 51722202 and 51972118), the Guangdong Provincial Science & Technology Project (2018A050506004) and the Fundamental Research Funds for the Central Universities (D2190980).
Аннотация: Highly efficient phosphors with thermal stability and color-tunable emission are required for the fabrication of phosphor-converted white light-emitting diodes (pc-WLEDs). Currently developed engineering strategies are generally successful in photoluminescence tuning but, unfortunately, suffer severe deterioration in emission intensity/efficiency and/or thermal stability. Herein, an efficient aliovalent substitution strategy toward reinforced structural rigidity is proposed and demonstrated experimentally. By incorporating Be2+ ion into the garnet-type Lu2SrAl4SiO12:Ce3+ phosphor, the phosphor shows enhanced internal/external quantum efficiency, from 79.2%/26.7% to 84.5%/32.9%, photoluminescence tuning from green (peaking at ∼512 nm) to yellow (peaking at ∼552 nm), and zero thermal quenching, even up to 200 °C. The Be2+ substitution at the Al2/Si2 site enables stable and rigid local surroundings around the Ce3+ activator, which is responsible for the unprecedented performance. In addition, high-quality warm WLED devices with a luminous efficiency of 158.1 lm W-1, correlated color temperature of 3858 K and high color rendering index of 81.7, are obtained by combining Lu2SrAl4SiO12:Ce3+,Be2+ as the yellow emitter, CaAlSiN3:Eu2+ as the red emitter and a blue-emitting InGaN chip. These findings highlight a new strategy for performance optimization of LED phosphors by selecting rigid covalent compounds with further reinforced structural rigidity via aliovalent substitution.
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20.

Вид документа : Статья из журнала
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Автор(ы) : Denisova L. T., Molokeev M. S., Irtyugo L. A., Beletskii V. V., Belousova N. V., Denisov V. M.
Заглавие : Structure and thermodynamic properties of the SmGaGe2O7 oxide
Место публикации : Phys. Solid State. - 2020. - Vol. 62, Is. 2. - P.384-387. - ISSN 10637834 (ISSN), DOI 10.1134/S1063783420020109
Примечания : Cited References: 10. - This study was carried out within the state assignment of the Ministry of Science and Higher Education of the Russian Federation to the Siberian Federal University in 2017–2019, project no. 4.8083.2017/8.9 “Formation of a Data Bank of Thermodynamic Characteristics of the Complex-Oxide Multifunctional Materials Containing Rare and Scattered Elements.”
Аннотация: The SmGaGe2O7 oxide material has been obtained from initial Sm2O3, Ga2O3, and GeO2 oxides by solid-phase synthesis with annealing in air in the temperature range of 1273–1473 K. The structure of the investigated germanate (sp. gr. P21/c, a = 7.18610(9) Å, b = 6.57935(8) Å, and c = 12.7932(2) Å) has been established by X-ray diffraction and the high-temperature heat capacity has been determined by differential scanning calorimetry. Using the experimental data on Cp = f(T), the thermodynamic properties of the compound have been calculated.
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