Effect of magnetic field on the reconstruction of the defect-impurity state and сathodoluminescence in Si/SiO₂ structure

Impurity states in Si/SiO₂ structure have been studied using cathodoluminescence (CL). It has been found that intrinsic structure defects in Si/SiO2 are sensitive to the action of magnetic field, which can be revealed due to changes in Si/SiO₂ optical properties. The most sensitive to magnetic field (about 35 per cent) is the intensity of the 1.9 eV CL band attributed to non-bridge oxygen atoms

Magnetization spin dynamics in a (LuBi)(3)Fe5O12 (BLIG) epitaxial film

Bismuth substituted lutetium iron garnet (BLIG) films exhibit larger Faraday rotation, and have a higher Curie temperature than yttrium iron garnet. We have observed magnetic stripe domains and measured domain widths of 1.4 μm using Fourier domain polarization microscopy, Faraday rotation experiments yield a coercive field of 5 Oe. These characterizations form the basis of micromagnetic simulations that allow us to estimate and compare spin wave excitations in BLIG films. We observed that these films support thermal magnons with a precessional frequency of 7 GHz with a line width of 400 MHz. Further, we studied the dependence of precessional frequency on the externally applied magnetic field. Brillouin light scattering experiments and precession frequencies predicted by simulations show similar trend with increasing field

Investigations of LiNb1−xTaxO3 nanopowders obtained with mechanochemical method

Nanocrystalline compounds LiNb1−xTaxO3 of various compositions (x = 0, 0.25, 0.5, 0.75, 1) were synthesized by high-energy ball milling of the initial materials (Li2CO3, Nb2O5, Ta2O5) and subsequent high-temperature annealing of the resulting powders. Data on the phase composition of the nanopowders were obtained by X-ray diffraction methods, and the dependence of the structural parameters of LiNb1−xTaxO3 compounds on the value of x was established. As a result of the experiments, the optimal parameters of the milling and annealing runs were determined, which made it possible to obtain single-phase compounds. The Raman scattering spectra of LiNb1−xTaxO3 compounds (x = 0, 0.25, 0.5, 0.75, 1) have been investigated. Preliminary experiments have been carried out to study the temperature dependences of their electrical conductivit

Magnetic force microscopy of YLaFeO films implanted by high dose of nitrogen ions

The scattering field gradient maps of surface layer magnetic domains in Y₂.₉₅La₀.₀₅Fe₅O₁₂ iron-yttrium garnet modified by high-dose ion implantation with nitrogen ions N+ were obtained by the method of magnetic force microscopy. It was found that improving the magnetic properties of thin films, which includes reducing the observed magnetic losses after high-dose implantation, is accompanied by essential ordering of magnetic domains on the surface of the implanted films. There is a direct dependence of the magnetic properties on the dose of implanted atoms, accompanied by a significant dispersion and amorphization of surface layer and formation of a clear magnetic structure

X-ray excited luminescence of ytterbium containing YAG single crystalline films

Luminescence properties of ytterbium ions in of У₃AI₅О₁₂ (УAG) epitaxial films have been investigated. The influence of growth conditions on the change of activator ions charge state and the luminescence in visible spectral region has been demonstrated. It has been established that emission bands with maxima at 480 and 580 nm are attributed to the 5d-4f transitions of Уb²⁺ ions. The emission bands with maxima at 330 nm and 500 nm correspond to transitions from charge transfer state to ²F₇/₂ and and ²F₅/₂ state of Уb³⁺ ions, respectively.Проведено исследование люминесцентных свойств ионов иттербия в эпитаксиальных пленках У₃AI₅О₁₂ (УAG). Показано влияние условий выращивания на изменение зарядового состояния ионов активатора и его свечения в видимой области спектра. Установлено, что люминесценция в полосах с максимумами при 480 нм и 580 нм в эпитаксиальных пленках УAG:Уb приписывается 5d-4f переходам ионов Уb²⁺. Полосы свечения с максимумами при 330 и 500 нм отвечают переходам из состояния переноса заряда соответственно на уровни ²F₇/₂ и ²F₅/₂ ионов Уb³⁺.Проведено дослiдження люмiнесцентних властивостей iонiв iтербiю в епiтаксiйних плiвках У₃AI₅О₁₂ (УAG). Показано вплив умов вирощування на змiну зарядового стану iонiв активатора та його свiчення у видимiй областi спектра. Встановлено, що люмiнеcценцiя в смугах з максимумами при 480 нм i 580 нм приписується 5d-4f переходам iонiв Уb²⁺. Смуги свiчення з максимумами при 330 i 500 нм вiдповiдають переходам зi стану перенесення заряду вiдповiдно на рiвнi ²F₇/₂ i ²F₅/₂ iонiв Уb³⁺

Optical Absorption and Luminescence of Gd3Ga5O12:Cr,MgGd_{3}Ga_{5}O_{12}:Cr,Mg Epitaxial Films

The optical absorption, emission spectra and luminescence decay kinetics under photoexcitation of $Gd_{3}Ga_{5}O_{12}$ (GGG) garnet epitaxial films doped with $Cr^{3+}$ ions and co-doped with $Cr^{3+}$ and $Mg^{2+}$ ions have been investigated. Luminescence of the GGG:Cr films due to $\text{}^{4}T_{2}$ → $\text{}^{4}A_{2}$ and $\text{}^{2}E$ → $\text{}^{4}A_{2}$ transitions in $Cr^{3+}$ ions have been observed. Increase of the activator ions concentration has an influence on the intensity and decay time of $Cr^{3+}$ ions photoluminescence. Introduction of the magnesium ions leads to partial transformation of chromium valence state $(Cr^{3+} \rightarrow Cr^{4+})$ and to the appearance of a broad absorption band with the maximum at 860 nm. The narrow lines with luminescence maxima at 704 and 706 nm have arisen in the highly doped GGG:Cr,Mg films

Optical in situ Study of Reduction/Oxidation Processes in Cr,Mg:YAG Epitaxial Film

The changes of the optical absorption spectra of Cr,Mg:YAG epitaxial film caused by high-temperature redox treatment are investigated by means of in situ spectroscopy. The spectra were registered in the visible and near-IR spectral regions at temperatures up to 1100 K. The kinetics of optical absorption changing were obtained in the temperature range from 936 K to 1091 K and were described by mathematical model connecting the chromium recharging process with oxygen vacancies diffusion. The parameters of the model were determined from the approximations of the experimental kinetics

Optical Properties of GGG Epitaxial Films Grown from PbO-B₂O₃-V₂O₅ Flux

The paper reports a growth of the high-quality Gd₃Ga₅O₁₂ (GGG) homoepitaxial films by the liquid phase epitaxy technique using the PbO-B₂O₃ and PbO-B₂O₃-V₂O₅ fluxes. The influence of the flux composition containing V₂O₅ as well as the growth temperature is discussed basing on the optical absorption and the electron probe micro analysis results

Electrical properties of n‑HgCdTe MIS structures with HgTe single quantum wells

Hg1−xCdxTe grown by molecular beam epitaxy including HgTe single quantum well (SQW) with thickness of 6.5 nm wer