Experimental results are presented on radiation-optical studies of yttrium aluminum garnets (YAG) nonactivated and activated with rare earth ions (Y3Al5O12-TR3+) and phosphate glasses activated with Nd3+ ions. Changes in radio- and thermoluminescence spectra are shown to be strongly affected by the mechanisms of phonon scattering by point defects.

The paper presents the results of magnetic and optical studies of the 25K 2 O center dot 25Al 2 O 3 center dot 50B 2 O 3 glasses pure and with 0.1-3.0 wt% Fe 2 O 3 additions subjected to thermoradiation treatment in a converging 60 Co gamma field at a dose rate of 236 R/s and temperatures of 423-573 K. After the treatment the absorption spectra and magnetization were measured. The second negative absorption band was referred to the transition Fe 2 O 3 and Fe 3 O 4 formation at high temperature gamma - irradiation. SQUID magnetometry of the glass with 2-3 wt% Fe 2 O 3 revealed isolated iron ions and Fe 2 O 3 particles with small hysteresis loop.

The paper presents the results of studying magnetic properties of the K _2 O · Al _2 O _3· B _2 O _3 (KAB) glasses with the addition of 2.0 and 3.0 wt % Fe _2 O _3 , subjected to radiation treatment in ^60 Co gamma-field at a dose rate of 236 R/s for 2 h at room temperature and when the samples are heated to 423 K. Under both radiation and thermoradiation exposure, the magnetic susceptibility of glasses follows the Curie–Weiss law at 4.2–200 K and slightly deviates from this dependence at 200–340 K. The weakly pronounced magnetic hysteresis with low coercive force was found at low temperatures against the background of magnetization that depends almost linearly on the field. The analysis of data on the temperature and field dependences of magnetization in weak and strong fields, combined with data on structural and optical properties, indi-cates that mainly Fe _2 O _3 nanoparticles in the uncompensated antiferromagnetic state, as well as an insignificant amount of dissociated Fe and Fe _3 O _4 ions, are formed in glasses.

Методом твердофазного синтеза получены ВЭО BaFe12-x(Ti,Mn,In,Ga)xO19(x=1, x=7). Исследована корреляция химического состава (степень замещения Fe), структурных параметров, магнитных характеристик. Магнитные характеристики ВЭО BaFe12-x(Ti,Mn,In,Ga)xO19 (x=1, x=7) были исследованы в широком диапазоне полей и температур. Измерены инфракрасные спектры коэффициента отражения образцов BaFe12-x(Ti,Mn,In,Ga)xO19 (x=1, x=7), содержащие особенности, связанные с фононными колебаниями. Выполнен качественный анализ зависимости характеристик фононных линий от концентрации x, а также сравнение спектров со спектрами монокристаллического образца состава BaFe12O19.

The BaFe12–x(Ti,Mn,In,Ga)xO19(x = 1, x = 7) HEOs are prepared by a solid-phase synthesis. Correlations between the chemical composition (degree of Fe substitution), structural parameters, and magnetic characteristics are studied. Magnetic characteristics of the BaFe12–x(Ti,Mn,In,Ga)xO19 (x = 1, x = 7) HEOs are studied in a wide range of fields and temperatures. The measured IR reflectance spectra of the samples contain features caused by phonon vibrations. The dependence of characteristics of phonon lines on the concentration x is qualitatively analyzed; the obtained spectra are compared with those of a single-crystal BaFe12O19 sample.

Glasses of K $${}_{2}$$ O $$\cdot$$ Al $${}_{2}$$ O $${}_{3}\cdot$$ B $${}_{2}$$ O $${}_{3}$$ composition with Fe $${}_{2}$$ O $${}_{3}$$ additives from 0.1 to 3.0 wt $$\%$$ subjected to thermoradiation treatment at irradiation temperatures of 423, 473, 523, and 573 K in a $${}^{60}$$ Co gamma field at a dose rate of 236 R s $${}^{-1}$$ have been structurally studied. X-ray diffraction spectra revealed the crystal structure of nanosized inclusions of iron oxides, magnetite phase, and hematite phase in grid glass. SEM has shown that gamma irradiation at doses of $$(0.3-1.0)\times 10^{6}$$ R reduces the initial surface roughness from 0.5 to 0.1 $$\mu$$ m, and thermoradiation treatment significantly polishes the surface.

In this work, the magnetic fluids based on Fe 3 O 4 have been obtained by the chemical co-precipitation method. Analysis of the size and morphology of the synthesized iron oxide nanoparticles of the magnetic fluid using transmission electron microscopy revealed that nanoparticles are of 25-38 nm in size and spherical in shape. The elemental composition of magnetite nanoparticles of the fluid was examined in energy-dispersive X-ray analysis and determined to contain only Iron and Oxygen. The magnetic property of the magnetic fluid was measured using vibrating sample magnetometer. The results showed that the magnetic fluid has a superparamagnetic character which of specific saturation magnetization of 3.4 emu/g

For laser phosphate glasses activated by pairwise neodymium and cerium ions, a number of radiation-optical effects have been studied: thermal and thermoradiative decolorization in the region of 200-800 nm; jump-like switching of the valence of cerium ions during the valencecoordination change in its oxygen environment. A new conceptual approach is proposed to the mechanism of the thermoradiation effect of gamma irradiation at temperatures of 100-400 C, leading to the detection of neodymium-neodymium and neodymium-cerium ion-ion coordination interactions in nano-structural complex complexes involving the structure of a glass matrix, Only thermoradiation exposure.

Nonlinear effects observed via EPR spectroscopy in potassium–aluminum–borate glasses with iron oxide additives after exposure to gamma irradiation of a 60 Co source are discussed. The effects are due to the interaction of gamma irradiation with glass which leads to nonlinear dependences of the intensity of radiation-induced EPR spectrum on the dose of gamma irradiation.

This paper presents the results of thermoradiation modification of nanostructure of potash-aluminum-boron glasses with iron oxide additives studied by optical spectroscopy. The differential spectra of the glass samples have jumps at 240, 320 and 370 nm. The physical mechanism of their formation is suggested. The obtained results show the way for the nanostructure modification useful for magneto-optical and dosimetric applications of the glasses. Valence-coordination transition of iron ions induced by irradiation at elevated temperatures can be used as switching effect in quantum computers. (C) 2018 Elsevier B.V. All rights reserved.

The radiation effect on the light absorption by potassium-alumina-borate glasses with iron oxide additives of various concentrations was studied at different sample thicknesses. It was shown that, in contrast to samples of small thickness (1 mm), a bleaching effect was observed in samples with a thickness of 8 mm. A possible mechanism of the revealed bleaching effect associated with the formation of nanostructured units is considered.

The effect of radiation on the absorption of light by potassium–alumina–borate glasses with various concentrations of iron additions and various thicknesses was investigated. It was shown that in contrast to samples of small thickness (1 mm) a bleaching effect was observed in the samples with a thickness of 8 mm. A possible mechanism involving the formation of nanostructured units is proposed for the observed effect.

This work experimentally revealed, that 60Co-gamma-irradiation of potash-alumina-borate glasses doped with 1 and 2 mass% of iron oxide to the dose of 1.7 MR in the temperature range of 150–300 °C induced differential optical density changes within − 6 ≤ ΔD ≤ 0 in the wave length range of 300–350 nm, which is characteristic for meta-material. Calculations have shown that variation of optical refraction index within − 0.05 ≤ Δn ω  ≤ 0.05 due to microstructure transformation causes changes in the differential absorption index of the glass − 0.5 < Δα ω  < 0.55.

The interaction of superconductivity and magnetism in the compounds with rare-earth represents a high scientific interest, in connection with a rapid progress which has been reached in this area within the last ten years. The compounds of rare-earth metals give possibility to investigate interaction between the superconducting phase and distant magnetic order in them as so as atoms of rare-earth elements form spatially-ordered state in its sub-lattice. Hence, unique superconducting and magnetic properties of triple compounds are connected with feature of their crystal structure and stoichometry.In this work we studied magnetic properties of CeAgSb2 upon various dozes of gammaradiation. The crystal was synthesized at 1073 K, its magnetic properties CeAgSt> 2 were investigated by Faraday method. The experimental curve of magnetic susceptibility in the temperature interval (393-873 K) before irradiation has a …

The spectral-luminescent and photo-physical characteristics of some squaraine dyes, which fluoresce in red spectral range—most suitable for medical-biological investigation, were studied. The charge distribution and structural parameters of these dyes were calculated by semi-empirical AM1 method. It was found that the absorption and fluorescence spectra of water soluble dyes I–III solutions remain invariable over wide concentrations range (10−4–10−6 M). This testifies that dyes' molecules in solution exist in monomer form; the wavelength maxima of absorption and fluorescence bands, extinction coefficients, strength of oscillators, radiational lifetimes of excited state, quantum yield of fluorescence and frequencies of 0–0 transitions were determined for them. The interaction of these water soluble dyes with biological objects was studied. It was found, that the addition of enzyme gialuronidaze (64 units) to water solution of dye II, at constant concentration (2×10−6 M) of dye, leads to the drop of absorptive and fluorescent abilities of solution and to the broadening of absorption spectrum. The addition of this enzyme to water solution of dye III leads to the appearance of a new emission band at λmax=702 nm in fluorescence spectrum and to the intensification of emission on this band at further increase of enzyme concentration in the solution. The binding parameters of dye molecules with bovine serum albumin were determined as well.