scholarly journals Отражение от боковой грани кристалла PbSb-=SUB=-2-=/SUB=-Te-=SUB=-4-=/SUB=-

2020 ◽  
Vol 54 (3) ◽  
pp. 228
Author(s):  
С.А. Немов ◽  
Ю.В. Улашкевич ◽  
М.В. Погумирский ◽  
О.С. Степанова
Keyword(s):  
Experimental Data ◽  
Crystal Lattice ◽  
Room Temperature ◽  
Polarized Light ◽  
Spectral Features ◽  
Reflection Spectra ◽  
Lattice Vibrations ◽  
Lorentz Model ◽  
Plasma Oscillations ◽  
Side Face

The reflection spectra from the side face of a PbSb2Te4 crystal were measured by room temperature in polarized light in the range 50-4000 cm-1. Significant anisotropy of the crystal is shown in the directions along and across the crystal layers. The revealed spectral features are interpreted by the contribution of plasma oscillations and crystal lattice vibrations. The calculated dielectric function parameters in the framework of the Drude-Lorentz model are consistent with experimental data.

Das Kombinationsschwingungsspektrum von Gips im Bereich von 10 000—1200 cm-1

1968 ◽  
Vol 23 (5) ◽  
pp. 708-715 ◽  
Author(s):  
V. Hohler ◽  
H. D. Lutz
Keyword(s):  
Hydrogen Bonds ◽  
Ir Spectrum ◽  
Room Temperature ◽  
Polarized Light ◽  
Water Molecules ◽  
Lattice Vibrations ◽  
Frequency Range ◽  
Sulfate Ions ◽  
Normal Vibrations

The IR-spectrum of gypsum (CaSO4·2 H2O) in the frequency range from 10 000 to 1200 cm-1 has been investigated with polarized light at room temperature. Between 3700 and 1200 cm-1, the measurements confirm the data of HASS and SUTHERLAND and as well as those of SCHAAK derived from IR and reflection measurements. The IR-spectrum shows a great number of bands, most of which can be assigned to combination and fundamental vibrations in terms of normal vibrations of the water molecules and the sulfate ions. The influence of the lattice vibrations is briefly discussed. The existence of hydrogen bonds between the water molecules and the sulfate ions gives rise to combinations of fundamental vibrations of both complexes.

Applications of the Theory of Optical Spectroscopy to Numerical Simulations

1993 ◽  
Vol 47 (5) ◽  
pp. 566-574 ◽  
Author(s):  
M. Milosevic ◽  
S. L. Berets
Keyword(s):  
Experimental Data ◽  
Optical Constants ◽  
Incident Angle ◽  
Spectroscopic Technique ◽  
Sample Thickness ◽  
Spectroscopic Techniques ◽  
Spectral Features ◽  
Reflection Spectra ◽  
Experimental Conditions ◽  
Potential Applications

A numerical simulation has been developed to extract the optical constants from experimental spectra. In particular, transmission, internal reflection, and external reflection spectra can be simulated for any incident angle, polarization, and sample thickness. The simulation is used here to determine the optical constants of two materials and to illustrate differences in spectral features that arise from variations in experimental conditions. Other potential applications of this method include determining film thicknesses from experimental data, selecting the best spectroscopic technique for a particular sample, and cross-referencing spectroscopic techniques.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Spontaneous Formation ◽  
The Stability ◽  
Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

scholarly journals Подвижность ионных носителей заряда в пьезоэлектрических кристаллах Li-=SUB=-2-=/SUB=-B-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=-

2020 ◽  
Vol 62 (3) ◽  
pp. 386
Author(s):  
Н.И. Сорокин ◽  
Ю.В. Писаревский ◽  
В.В. Гребенев ◽  
В.А. Ломонов
Keyword(s):  
Crystal Lattice ◽  
Carrier Mobility ◽  
Room Temperature ◽  
Lithium Ion ◽  
Structural Data ◽  
Crystallographic Axis ◽  
Frequency Range ◽  
Impedance Measurements ◽  
Structural Mechanism ◽  
Ag Electrodes

The impedance measurements of Li2B4O7 single crystal with Ag electrodes in the frequency range 1-3*107 Hz at room temperature have been made. The Li2B4O7 crystal (sp. gr. I41cd, Z = 8) was oriented along crystallographic axis c. Contributions from the bulk crystal and crystal / electrode boundaries in the impedance hodograph of the Ag | Li2B4O7 | Ag system were selected. The structural mechanism of lithium-ion transport in Li2B4O7 has been discussed. Based on electrophysical and structural data, the conductivity σdc = 2.3 × 10–9 S / cm, carrier mobility (vacancies VLi) μmob = 6 × 10−10 cm2 / sV and their concentration nmob = 2.4 × 1019 cm – 3 (0.14% of the amount of lithium in the crystal lattice) have been determined.

scholarly journals Aluminum nitride doped with transition metal group atoms as a material for spintronics

2020 ◽  
pp. 162-172
Author(s):  
S.S. Khludkov ◽  
◽  
I.A. Prudaev ◽  
L.O. Root ◽  
O.P. Tolbanov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Magnetic Properties ◽  
Molecular Beam Epitaxy ◽  
Transition Metal ◽  
Aluminum Nitride ◽  
Room Temperature ◽  
Molecular Beam ◽  
Scientific Literature ◽  
Material Growth ◽  
Metal Group

Aluminum nitride doped with transition metal group atoms as a material for spintronics The overview of scientific literature on electric and magnetic properties of AlN doped with transition metal group atoms is presented. The review is based on literature sources published mainly in the last 10 years. The doping was carried out by different methods: during the material growth (molecular beam epitaxy, magnetron sputtering, discharge techniques) or by implantation into the material. The presented theoretical and experimental data show that AlN doped with transition metal group atoms has ferromagnetic properties at temperatures above room temperature and it is a promising material for spintronics.

scholarly journals Spectral Fourier-microscopy of the periodic structures based on Ge2Sb2Te5

2021 ◽  
Vol 2103 (1) ◽  
pp. 012173
Author(s):  
A I Solomonov ◽  
S I Pavlov ◽  
P I Lazarenko ◽  
V V Kovalyuk ◽  
A D Golikov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Reasonable Agreement ◽  
Angular Resolution ◽  
Periodic Structures ◽  
Diffraction Gratings ◽  
Dispersion Curves ◽  
Reflection Spectra ◽  
Waveguide Modes ◽  
Periodic Gratings

Abstract The method of spectral Fourier microscopy was used to study the reflection spectra with an angular resolution of submicron periodic gratings based on amorphous and crystalline Ge2Sb2Te5. The form of the dispersion curves of quasi-waveguide modes in the structures under study was established. The experimental data were compared with the calculations of dispersion curves in synthesized diffraction gratings. Reasonable agreement between theoretical and experimental data was obtained.

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