Częstochowa, Poland
Częstochowa, Poland

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Piasecki M.M.,ugosz University Czestochowa | Andriyevsky B.B.,Koszalin University of Technology | Cobet C.C.,Leibniz Institute for Analytical Sciences | Esser N.N.,Leibniz Institute for Analytical Sciences | And 3 more authors.
Optics Communications | Year: 2010

Substantial influence of the 1 at.% Yb doping of NdGaO3 single crystals on the optical functions ε1(E) and ε 2(E) in the spectral range of electronic excitations is established. The corresponding differences of the optical functions for pure and doped NdGaO3 have been monitored using spectroscopic ellipsometry method and synchrotron radiation light source. This opens an opportunity for the spectroscopic diagnostics of the rare earth dopants in crystals using the spectroscopic information concerning the electronic inter-band optical transitions. To understand better the experimental results obtained, the ab-initio calculations of band structure and optical spectra of the centrosymmetric single crystal NdGaO3 have been performed using the VASP code (Vienna Ab-initio Simulation Package). The calculated dielectric functions ε1(E) and ε2(E) agree satisfactorily with our experimental results obtained with using the spectroscopic ellipsometry method and synchrotron radiation. It was demonstrated that differences of the optical functions for pure and doped crystals using stable synchrotron source may serve as a powerful tool for spectroscopic diagnostic of localised rare earth ions with respect to the strong inter-band transitions. © 2010 Elsevier B.V.

Majchrowski A.,Military University of Technology | Sahraoui B.,CNRS Angers Institute of Molecular Science and Technology | Fedorchuk A.O.,Lviv National University of Veterinary Medicine and Biotechnologies | Jaroszewicz L.R.,Military University of Technology | And 3 more authors.
Journal of Materials Science | Year: 2013

Studies of optical second harmonic generation (SHG) at fundamental wavelength of 1064 nm under photoinducing treatment of monoclinic piezoelectric β-BaTeMo2O9 (β-BTMO) were done. Continuous wave (CW) lasers generating at 808 and 1040 nm were used as photoinducing sources. The investigations were performed for the β-BTMO microcrystalline powder samples with grain sizes varying within the 25-300 μm range. We showed that depending on the microcrystallites size, the photoinduced changes of the SHG were substantially different depending on number of defects which were controlled by positron annihilation. The photoinduced SHG efficiency was substantially higher for more defective crystallites. The processes are completely reversible; however, their photoinduced time kinetics is very sensitive to the wavelength of the photoinducing CW laser beam. The possible reasons for the observed differences are discussed within a framework of intrinsic defect trapping levels and their interactions with phonon subsystem. © 2013 Springer Science+Business Media New York.

Piasecki M.,ugosz University Czestochowa | Myronchuk G.L.,European University at Kiev | Zamurueva O.V.,European University at Kiev | Khyzhun O.Y.,Ukrainian Academy of Sciences | And 6 more authors.
Materials Research Express | Year: 2016

It is shown that narrow band gap semiconductors Tl1xIn1xGexSe2 are able effectively to vary the values of the energy gap. DFT simulations of the principal bands during the cationic substitutions is done. Changes of carrier transport features is explored. Relation with the changes of the near the surface states is explored . Comparison on a common energy scale of the x-ray emission SeKβ2 bands, representing energy distribution of the Se 4p states, indicates that these states contribute preliminary to the top of the valence band. The temperature dependence of electrical conductivity and spectral dependence photoconductivity for the Tl1xIn1xGexSe2 single crystals were explored and compared with previously reported Tl1xIn1xGexSe2. Based on our investigations, a model of centre re-charging is proposed. Contrary to other investigated crystals in Tl1xIn1xGexSe2 single crystals for x=0.1 we observe extraordinarily enormous photoresponse, which exceed more than nine times the dark current. X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated surfaces of Tl1xIn1xGexSe2 (x=0.1 and 0.2) single crystals have been studied. These results indicate that the relatively low hygroscopicity of the studied single crystals is typical for the Tl1xIn1xGexSe2 crystals, a property that is very important for handling these quaternary selenides as infrared materials operating at ambient conditions. © 2016 IOP Publishing Ltd.

Lyutyy P.,NASU Karpenko Physico Mechanical Institute | Lyutyy P.,ugosz University Czestochowa | Niehaus O.,University of Munster | Svitlyk V.,University of Munster | And 4 more authors.
Solid State Sciences | Year: 2014

New ternary compounds have been obtained from arc-melting of the elements. The crystal structures have been investigated by powder X-ray diffraction analysis. DyAl0.33Ga2.67 crystallizes in space group P63/mmc (a = 6.1649(1) Å, c = 23.0792(1) Å) with Ta(Rh0.33Pd0.67)3-type structure. The structure of DyAl0.85Ga2.15 has been refined with rhombohedral symmetry (space group R-3m, a = 6.1702(1) Å, c = 20.7797(1) Å), BaPb3-type structure. The structures of the compounds have been analyzed crystallographically and the structural relationship has been established. Heat capacity measurements prove antiferromagnetic ordering at Néel temperatures of 12.6(1) K for DyAl0.33Ga2.67 and 10.0(1) K for DyAl0.85Ga2.15. © 2014 Elsevier Masson SAS. All rights reserved.

Lyutyy P.,NASU Karpenko Physico Mechanical Institute | Lyutyy P.,ugosz University Czestochowa | Niehaus O.,University of Munster | Pottgen R.,University of Munster | And 5 more authors.
Solid State Sciences | Year: 2014

The NiGa0.82Si0.18, NiGa0.84Ge 0.16 and NiAl0.46Si0.54 phases have been obtained from arc-melting of the elements. Crystal structures have been refined in a cubic symmetry (P213 space group, a = 4.6197(6), 4.6393(2) and 4.5543(4) Å, respectively) using powder X-ray diffraction data. Crystallographic relationship between the NiGa0.82Si0.18, NiGa0.84Ge0.16 and NiAl0.46Si0.54 compounds and all binary compounds in the Ni-Ga system have been established. The ternary compounds have been found to be thermally stable up to 1500 K, as was concluded by the DSC measurements. In addition, the NiGa 0.82Si0.18 and NiGa0.84Ge0.16 phases each exhibit two exothermic transitions at 1136 K, 1367 K and 1043 K, 1389 K, respectively. NiAl0.46Si0.54 shows one exothermic transition at 1287 K. From the magnetic susceptibility measurements all compounds have been found to be Pauli paramagnets. © 2014 Elsevier Ltd. All rights reserved.

Kogut Y.,Lesya Ukrainka Eastern European National University | Khyzhun O.Y.,Ukrainian Academy of Sciences | Parasyuk O.V.,Lesya Ukrainka Eastern European National University | Reshak A.H.,University of South Bohemia | And 5 more authors.
Journal of Crystal Growth | Year: 2012

In this paper, we report on novel Ag 0.5Pb 1.75GeS 4 single crystals grown by the Bridgman-Stockbarger method. For these crystals we have performed X-ray photoelectron spectroscopy (XPS) studies of the valence-band and core-level electron states. Second harmonic generation efficiency of Ag 0.5Pb 1.75GeS 4 powder samples by using CO 2 laser light depending on the power density up to 1100 MW/cm 2 has been obtained within the temperature range 77-520 K. The obtained dependences indicate relatively strong enhancement of photoinduced SHG output efficiencies as temperature increases. Both the spectra taken at ambient and 520 K temperatures have shown similar behavior - rapid growth to saturated values of SHG efficiency with an increase of fundamental beam power density up to 400 MW/cm 2, then slowly decreasing with power density reaching a value of 800 MW/cm 2 and finally these features show a second small maximum at a fundamental beam power density equal to 900 MW/cm 2. Beyond this power density both SHG values start to decrease. © 2012 Elsevier B.V.

Khyzhun O.Y.,Ukrainian Academy of Sciences | Kityk I.V.,Czestochowa University of Technology | Piasecki M.,ugosz University Czestochowa | Fedorchuk A.O.,Lviv National University of Veterinary Medicine and Biotechnologies | And 4 more authors.
Physica B: Condensed Matter | Year: 2015

Tl4HgBr6 single crystals were grown using solution-fusion method. The crystal structure of the ternary bromide was refined. Tl4HgBr6 crystallizes in the non-centrosymmetric space group P4nc with the lattice parameters a=8.9539(8) Å and c=8.7884(8) Å and it is isostructural to the Tl4HgI6 compound. The non-centrosymmetric structure of the Tl4HgBr6 compound was also confirmed by the existence of a modest second harmonic generation effect (0.4-0.5 pm/V) and by the value of piezoelectric coefficient (0.9 pm/V). The electronic structure of Tl4HgBr6 was explored using X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES). In particular, for the Tl4HgBr6 crystal, we have measured XPS core-level and valence-band spectra for both pristine and Ar+ ion-bombarded surfaces. The XPS data reveal low hygroscopicity of Tl4HgBr6, the property that is very important when handling this material in optoelectronic devices working at ambient conditions. The present XPS data indicate that the Tl4HgBr6 single crystal surface is rather sensitive with respect to Ar+ ion-bombardment: such a treatment reduces significantly mercury content in the topmost surface layers. Comparison on a common energy scale of the XPS valence-band spectrum of Tl4HgBr6 and the XE Br Kβ2 band, representing peculiarities of the energy distribution of the Br 4 p states, reveals that the main contribution of the valence Br p states occurs in the upper portion of the valence band, with also their significant contributions in other valence band regions. The measurements of spectral distribution of the absorption coefficient indicate that the Tl4HgBr6 compound is a semiconductor with the bandgap energy value of 2.43 eV at 300 K, and the bandgap energy increases up to 2.48 eV when temperature decreases to 100 K. © 2015 Elsevier B.V. All rights reserved.

Fedorchuk A.O.,Lviv National University of Veterinary Medicine and Biotechnologies | Gorgut G.P.,Lesya Ukrainka Eastern European National University | Parasyuk O.V.,Lesya Ukrainka Eastern European National University | Lakshminarayana G.,Los Alamos National Laboratory | And 2 more authors.
Journal of Physics and Chemistry of Solids | Year: 2011

In this work, we report on the structural and optical properties of novel Ag0.98Cu0.02GaGe3Se8 single crystals that were synthesized by the BridgmanStockbarger technique. We have performed illumination by 10.6 μm CO2 pulsed laser working in the microsecond time duration regime. Such illumination allows causing substantial changes for both pure electronic nonlinear optical effects like optical second harmonic generation as well as piezooptical effects described by the fourth rank tensors. The measurements of the piezo-optical effects were carried out at different temperatures. The effects are observed only during the IR CO 2 laser illumination and are disappeared after switching off the illumination. Simultaneously the IR induced optical second harmonic generation at Er:glass laser fundamental wavelength 1540 nm was performed during illumination by nanosecond Nd:YAG and Er3:glass laser. The observed effects allow to use the studied materials as promising for IR-optoelectronic devices. © 2011 Elsevier Ltd. All rights reserved.

Pavic L.,Ruder Boskovic Institute | Narasimha Rao N.,Krishna University | Mogus-Milankovic A.,Ruder Boskovic Institute | Santic A.,Ruder Boskovic Institute | And 4 more authors.
Ceramics International | Year: 2014

In continuation of our earlier work on some physical properties (non-linear optical effects, piezoelectric and elastic properties) of ZnF 2-PbO-TeO2:TiO2 glass ceramics, in the present study we have investigated the dielectric properties over a frequency range of 10-2 to 106 Hz and in the temperature range 303-523 K of these samples. The measurements include dielectric constant, ε′(ω), ac conductivity, σac, impedance spectra and electric modulus, M(ω). The temperature dispersion of real part of dielectric constant ε′(ω), has been analyzed using space charge polarization model. The ac conductivity exhibited maximal effect, whereas the activation energy for the conductivity demonstrated minimal value at 1.0 wt% of the crystallizing agent TiO2. In the low temperature region, the ac conductivity is nearly constant and varies linearly with frequency. Such behavior is explained following quantum mechanical tunneling (QMT) model. The dielectric relaxation effects for these samples have been analyzed quantitatively using the graphical method and spreading of relaxation times. The obtained results have been further analyzed quantitatively by Raman spectra. The variation of ac conductivity with the concentration of crystallizing agent was compared with second order susceptibility and the piezoelectric coefficient. The comparison indicated the phenomena responsible for the maximal effects for all the three parameters at 1.0 wt% of TiO2 are the same. © 2013 Elsevier Ltd and Techna Group S.r.l.

Srikumar T.,Acharya Nagarjuna University | Kityk I.V.,Czestochowa University of Technology | Srinivasa Rao C.,Acharya Nagarjuna University | Gandhi Y.,Acharya Nagarjuna University | And 4 more authors.
Ceramics International | Year: 2011

We have synthesized Li2O-Nb2O5-ZrO 2-SiO2 glasses and subsequently crystallized them with different CuO contents (0-0.3 mol% in the steps of 0.05) as nucleating agents and characterized them by XRD, SEM and DSC. We have also studied IR, Raman, ESR, optical absorption photoluminescence and dielectric properties to explore the influence of copper valance states and their coordination with oxygen on structural and optoelectronic aspects of the samples. These studies have indicated that there is a possibility for the copper ions to exist in Cu + and Cu3+ states (in addition to Cu2+ state) in these glass ceramics and participate in the glass network forming. Finally, we have undertaken photoinduced second harmonic generation studies (after the samples were dc field treated at elevated temperatures) with 10 ns Er:glass laser (of wavelength 1540 nm with power densities up to 1.5 GW/cm2) to examine the suitability of these materials for optically operated devices. The analysis of the results of non-linear optical studies has shown that 0.2 mol% of CuO is the optimal concentration for getting the highest values of second order susceptibility coefficients. © 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

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