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Your search keyword '"Sokovnin, S. Yu."' showing total 4 results
Start Over Author "Sokovnin, S. Yu." Topic luminescence
4 results on '"Sokovnin, S. Yu."'

1. New nanophosphors produced by evaporation of Sr2La8(1-x-y)ErxYbyGe6O26 polycrystals.

Author

Zuev, M. G., Vasin, A. A., Batalova, E. V., Il'ves, V. G., Sokovnin, S. Yu., Zhuravleva, E. Yu., Zyryanov, Grigory V, Santra, Sougata, and Sadieva, Leila K

Subjects
POLYCRYSTALS, LASER pumping, RAMAN spectroscopy, RADIATION, LUMINESCENCE
Abstract

Nanophosphors in the amorphous state was first obtained by electron beam evaporation of bulk phosphors with an oxyapatite structure of the composition Sr2La8(1-x-y)ErxYbyGe6O26(x = y = 0.01÷0.15). A modification of the Raman spectrum was detected with a decrease in particles from the micro- to nanoscale state. The luminescent characteristics of the samples in micro- and nanostates were studied. The dependences of the luminescence intensity of nanophosphors for some transitions on the pump radiation power are analyzed. A laser pump critical power of ∼75 mW was found for the lines caused by the 4S3/2→4I15/2, 4S3/2→4I15/2 and 4I9/2→4I15/2 transitions. The effect of the cross-relaxation of the 4I11/2+4I11/2→4I15/2+4F7/2 state on the 4I11/2 level of the Er3+ ion has been established. This process is dominant, equally affects the filling of the 2H11/2, 4S3/2, and therefore level 4F9/2. [ABSTRACT FROM AUTHOR]

Published
2020
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2. Luminescence Properties of Nanocrystalline BaF2 Synthesized by Laser Ablation Technique and Pulsed Electron Beam Evaporation Method.

Author

Shevelev, V. S., Ishchenko, A. V., Platonov, V. V., Sokovnin, S. Yu., Il'ves, V. G., and Shulgin, B. V.

Subjects
BARIUM fluoride, LASER ablation, ELECTRON beams, LUMINESCENCE, NANOPARTICLES, NANOELECTROMECHANICAL systems
Abstract

In this paper, studies of the effect of morphology and particle size of BaF2 nanopowders obtained by laser ablation method and by pulsed electron beam evaporation method on luminescent properties are presented. SEM-images of the morphology of all samples are presented. In the X-ray excited luminescence spectra of nanopowders, a redistribution of the relative intensity is observed between the self-trapped exciton and core-valence bands. This may be due to a smaller influence of particle size on the mechanism of formation of the cross-luminescence band. The change in the shape of the self-trapped exciton spectrum is also observed for nanosized samples. This effect can be associated with the possibility of the formation of certain STE configurations inside a nanoscale crystal due to the different relative position of the F and H centers parts with respect to each other. [ABSTRACT FROM AUTHOR]

Published
2018
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3. On the interrelationship of porosity and structural defects in amorphous-crystalline nanopowders SiO2-doped Gd2O3 with their magnetic and luminescent properties.

Author

Ilves, V.G., Murzakaev, A.M., and Sokovnin, S. Yu

Subjects
*POROSITY, *CRYSTAL defects, *SILICA nanoparticles, *GADOLINIUM compounds, *LUMINESCENCE, *MAGNETIC properties
Abstract

The pulsed electron beam evaporation method (PEBE) was used to obtain mesoporous amorphous-crystalline pure and SiO 2 -doped Gd 2 O 3 nanopowders (NPs). An HRTEM phase analysis showed the existence in nanopowder Gd 2 O 3 of an amorphous, as well as three crystalline phases. The influence of silicon oxide doping on the textural, magnetic and luminescent properties of NPs Gd 2 O 3 @SiO 2 was studied. The size and volume of the interparticle pores of NPs Gd 2 O 3 @SiO 2 was dependant on the concentration of a dopant. The doping supported an increase in amorphicity and the growth of a concentration of different structural defects in NPs. Two different processes – annealing and doping, led to crystallinity degradation of the Gd 2 O 3 matrix. The correlation of porosity concentration dependences, paramagnetic response, and the intensity of pulsed cathodoluminescence spectra in NPs Gd 2 O 3 @SiO 2 was revealed. The dependence of the paramagnetic response Gd 2 O 3 on the volume of interparticle mesopores in nonporous nanoparticles expands our understanding of the nature of diluted magnetic semiconductors. [ABSTRACT FROM AUTHOR]

Published
2018
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4. Effect of electron beam irradiation on the magnetic, thermal and luminescence properties of various oxide metal nanopowders.

Author

Balezin, M.E., Ilves, V.G., and Sokovnin, S. Yu

Subjects
*ELECTRON beams, *IRRADIATION, *SURFACE area, *LUMINESCENCE, *THERMAL stability
Abstract

Magnetic nanopowders of oxides Al 2 O 3 , SiO 2 , CeO 2 and YSZ (ZrO 2 -8% Y 2 O 3 ) with a high specific surface area irradiated in air by electrons with energy of 700 keV, pulse duration 100 ns, using the repetitively pulsed accelerator URT-1 within 15 and 30 min. The magnetic, thermal, and cathode luminescence characteristics of NPs were measured before and after irradiation. It was established that the electron irradiation non-monotonically changes the magnetization of the pristine samples. On the contrary, a clear correlation between the intensity of cathode luminescence and the irradiation dose is found in the most of the oxides. Thermal stability and phase transformations of unirradiated and irradiated CeO 2 and YSZ oxides were analyzed with the aid of synchronous analysis, using the methods of thermogravimetry and differential scanning calorimetry. The luminescent and thermal properties reflect the transformation of structural defects in NPs more strongly after exposure to a pulsed electron beam in comparison with corresponding changes of the NP's magnetic response. [ABSTRACT FROM AUTHOR]

Published
2018
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