Ellipsometric measurements of plastically deformed copper

Chemically pure copper (99.99) prepared in the sample of square cross-section (10 x 10 mm2) and length about 50 mm was extremely plastically deformed with the repeated application of equal channel angular pressing. Equal channel angular pressing was applied as an effective technique for producing bulk nanoscaled structures. It is well known that severe plastic deformation of metallic materials often leads to microstructure with ultrafine grains and cross-sections which remain about equal before and after deformation. Optical properties of the sample were studied using spectroscopic ellipsometry in UV-VIS range. The parameters of the sample like copper oxide and surface roughness overlayer were calculated using two-film model together with the Bruggeman effective medium approximation

Optical properties of plastically deformed copper

Pure copper (99.99), prepared in the sample of square cross-section (10 x 10 mm2) and length about 50 mm, was extremely plastically deformed with the repeated application of Equal Channel Angular Pressing (ECAP). ECAP was applied as an effective technique for producing bulk nano-scaled structures. Optical properties of the sample were investigated using Raman spectroscopy. Two types of lines: narrow (with width of 7 cm¡1) and wide ( 40 cm¡1) are registered. Existence of two types of lines indicates that in the specimen exists nano-sized crystal structures of both Cu and CuO related with three dimensional amorphous boundary spaces, which indicates that plastic deformation of the sample did not lead to total amorphisation of the specimen

Optical and Magnetic Properties of PbTe(Ni)

Far-infrared and magnetic properties of Ni doped PbTe (ZNi = 1 × 10 19 at./cm 3 ) single crystal are investigated in a broad range of temperature and magnetic fields. Far-infrared reflection spectra were analyzed using a fitting procedure based on the modified plasmon-two phonon interaction model. Together with the strong plasmon-two longitudinal optical phonon coupling we obtained a local mode of Ni at about 180 cm −1 . This mode intensity depends on temperature. Magnetic measurements shows that PbTe alloys doped with Ni reveals weak ferromagnetic interaction between magnetic ions

Optične lastnosti plastično deformiranega bakra: študij elipsometrije

In this paper the results of optical properties investigations on plastically deformed copper are presented. The optical properties of the plastically deformed copper were studied using spectroscopic ellipsometry in the ultraviolet-visible (UV-VIS) range. Chemically pure copper was deformed by applying the Equal Channel Angular Pressing (ECAP) technique. During the last decade, equal-channel angular pressing procedure was used for the fabrication of ultrafine-grained metals and alloys. The plastic deformation of metallic materials leads to the production of bulk nano-scale structures with ultrafine grains and cross-sections, which remain about equal before and after deformation. The parameters of the sample were calculated using a two-film model together with the Bruggeman effective medium approximation.V članku so predstavljeni rezultati raziskav optičnih lastnosti plastično deformiranega bakra. Te so bile raziskane s spektralno elipsometrijo v območju vidne UV-svetlobe. Kemijsko čist baker je bil deformiran z uporabo ECAP-metode (enakokotno koničasto stiskanje). V zadnjem času se ECAP-postopek uporablja za izdelavo ultra udrobnjenih kovin in zlitin. Takšna plastična deformacija kovinskih materialov vodi k izdelavi masivnih nanostruktur z ultra drobnimi zrni in prečnim prerezom, kar omogoča približno enakost pred deformacijo in po njej. Parametri preiskanih vzorcev so bili izračunani na osnovi uporabe dvojne plasti - filma skupaj s Bruggemanovo srednjo efektivno aproksimacijo

Kinetics of Solid-State Synthesis of Quaternary Cu₂FeSnS₄ (Stannite) Nanocrystals for Solar Energy Applications

In this study we demonstrate the use of elemental precursors (Cu, Fe, Sn, S) to obtain stannite forms by a solid-state one-pot mechanochemical synthesis. In the processing route, we report the kinetics of the synthesis. For the characterization of the unique nanostructures, X-ray diffraction, specific surface area measurements and SQUID magnetometry methods were applied. CFTS polymorphs with the tetragonal body-centered structure with the average crystallite size 18-19 nm were obtained. The weak ferromagnetic properties of the quaternary nanocrystals after maximum milling time were also documented

Modulated interference effect by ZnS nanoparticles / 3-Mercaptopropyltrimethoxysilane quasi core-shell structure: Far-infrared spectroscopy

The ZnS nanoparticles, as starting materials in the present study, were synthesized mechanochemically. Surface modification of the obtained nanoparticles was performed by 3-Mercaptopropyltrimethoxysilane. SEM analysis indicates that modification of ZnS nanoparticles with 3-Mercaptopropyltrimethoxysilane causes the appearance of the quasi core-shell structure. The FIR spectrum analysis was performed by fitting procedure, taking into account the appearance of quasi core-shell structure. Optical and structural characteristics of both ZnS and 3-Mercaptopropyltrimethoxysilanes are revealed on the spectrum. An interference effect modulated by the ZnS phonon properties was also detected. Obtained results indicate that the quasi core-shell structures could be successfully applied in the interferometry

Far-infrared spectra of mesoporous ZnS nanoparticles

ZnS nanoparticles were synthesized mechanochemically by high-energy milling, with three different milling times (5 min, 10 min and 20 min). Nitrogen adsorption method was used for examining specific surface area and texture of obtained powders. It was found that all samples are completely mesoporous. The optical properties were studied by far-infrared spectroscopy at room temperature in spectral region of 50-600 cm(-1). The analysis of the far-infrared reflectivity spectra was made by the fitting procedure. The dielectric function of ZnS nanoparticles is modeled as a mixture of homogenous spherical inclusions in air by the Maxwell-Garnet formula. In the analysis of the far-infrared reflection spectra, appearance of combined plasmon-LO phonon modes (CPPMs) with high phonon damping are observed, which causes decrease of coupled plasmon-phonon frequencies. (C) 2016 Elsevier B.V. All rights reserved

Ellipsometric Measurements of Plastically Deformed Copper

Chemically pure copper (99.99) prepared in the sample of square cross-section (10×10 $mm^{2}$) and length about 50 mm was extremely plastically deformed with the repeated application of equal channel angular pressing. Equal channel angular pressing was applied as an effective technique for producing bulk nanoscaled structures. It is well known that severe plastic deformation of metallic materials often leads to microstructure with ultrafine grains and cross-sections which remain about equal before and after deformation. Optical properties of the sample were studied using spectroscopic ellipsometry in UV-VIS range. The parameters of the sample like copper oxide and surface roughness overlayer were calculated using two-film model together with the Bruggeman effective medium approximation

Far-Infrared Study of DX-Like Centers in Pb0.95\text{}_{0.95}Mn0.05\text{}_{0.05}Te(Ga)

We present far-infrared reflection spectra of Pb$\text{}_{0.95}$Mn$\text{}_{0.05}$Te single crystal doped with gallium between 10 and 300 K. The analysis of the far-infrared reflection spectra was made by a fitting procedure based on the model of coupled oscillators. Together with the strong plasmon-phonon coupling we obtain three local modes of gallium at about 122 cm$\text{}^{-1}$, 166 cm$\text{}^{-1}$, and 192 cm$\text{}^{-1}$. The position of these modes depends on impurity center charge, and their intensity depends on temperature