Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 12

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  81.15.Jj
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Angular Distribution of Bremsstrahlung Photons in Ta Target for 40 MeV Electron Beam

100%
Demir N., Kuluöztürk Z., Akkurt İ.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 2B
B-443-B-444
EN
Bremsstrahlung photons are created by electron beams de-accelerating in electric field (coupling with a thin radiator) and are used in a variety of different fields. In nuclear physics experiments it is important to transport and focus the created photon beam into the experimental cavity. Here angular distribution of the photon beam is one of the important parameters, which should be known. In this study a FLUKA simulation has been done to obtain angular distribution of photon beam created by interaction of 40 MeV electron beam with the tantalum (Ta) radiator of varied thickness, which is planned to be used in bremsstrahlung photon facility at TARLA (Turkish Accelerator and Radiation Laboratory in Ankara). TARLA will be the first facility of Turkish Accelerator Center project.
2
Content available remote

GaN Layers Grown by Reactive Ion Plating

100%
Żubka A., Dwiliński R., Suchanek B., Janik W., Wysmołek A., Kwiatkowski S., Kamińska M., Shaginyan L.
Acta Physica Polonica A
|
1995
|
vol. 88
|
issue 5
1058-1062
EN
GaN layers grown on ceramics, sapphire or SiC substrates using reactive ion plating method are presented. In reactive ion plating method gallium from a hot source reacts on a heated substrate with nitrogen partially ionized. Rutherford backscattering technique was applied to check the composition of the samples and gallium to nitrogen ratio was found to be close to one. However, Rutherford backscattering studies showed also a remarkable amount of unintentional impurities present in the layers. The structure of GaN was determined using reflection high-energy electron diffraction. It appeared that polycrystal and monocrystal can be grown, depending on growth conditions. Absorption spectra taken on the layers grown on sapphire showed a tail of band to band absorption starting at about 370 nm. Carrier concentration was of the order of 1019-1020 cm^{-3} at room temperature and did not change much with temperature decrease. No luminescence from the layers was detected, most probably due to high concentration of impurities.
3
Content available remote

Anisotropic Magnetoresistance of Ni Nanorod Arrays in Porous SiO₂/Si Templates Manufactured by Swift Heavy Ion-Induced Modification

80%
Fedotova J., Ivanou D., Mazanik A., Svito I., Streltsov E., Saad A., Zukowski P., Fedotov A., Bury P., Apel P.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
894-896
EN
In this work anisotropic magnetoresistance in nanogranular Ni films and Ni nanorods on Si(100) wafer substrates was studied in wide ranges of temperature and magnetic field. To produce Ni films and nanorods we used electrochemical deposition of Ni clusters either directly on the Si substrate or into pores in SiO₂ layer on the Si substrate. To produce mesopores in SiO₂ layer, SiO₂/Si template was irradiated by a scanned beam of swift heavy 350 MeV ¹⁹⁷Au²⁶⁺ ions with a fluence of 5×10⁸ cm¯² and then chemically etched in diluted hydrofluoric acid. Pores, randomly distributed in the template have diameters of 100-250 nm and heights about 400-500 nm. Comparison of temperature dependences of resistance and magnetoresistance in Ni films and n-Si/SiO₂/Ni structures with Ni nanorods showed that they are strongly dependent on orientation of magnetic field and current vectors relative to each other and the plane of Si substrate. Moreover, magnetoresistance values in n-Si/SiO₂/Ni nanostructures can be controlled not only by electric field applied along Si substrate but also by additionally applied transversal bias voltage.
4
Content available remote

Different Wavelength Laser Irradiation of Amorphous Carbon

80%
Grigonis A., Rutkuniene Z., Vinciunaite V.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 1
26-29
EN
Coherent laser irradiation of amorphous carbon films formed on Si substrates by ion beam deposition from pure acetylene and acetylene/hydrogen gas mixture is analyzed in this work. The films were irradiated with nanosecond YAG:Nd laser (Ekspla NL301G) at the first (1064 nm, 6 ns), the second (532 nm, 4.2 ns) and the third (355 nm, 28 ns) harmonic by scanning or repeating (10 pulses to one point) regime. Irradiation by the first laser harmonic leads to a minor increase of graphite phase content and shows SiC formation. Formation of carbides was observed at the second harmonic irradiation when irradiation intensity is low (< 10 MW/cm^2). Graphitization became more intensive when power density of irradiation increased and the films transformed to the glass carbon and nano/micro crystallite compound at intensive ablation regime ( ≈ 24 MW/cm^2). Early ablation starts at irradiation by the third laser harmonic with the intensity of ≈ 8 MW/cm^2 with an increase of Si substrate roughness. Swelling of films was obtained when the sample was irradiated at the third harmonic with 1 MW/cm^2.
5
Content available remote

Technology of Ultrathin NbN and NbTiN Films for Superconducting Photodetectors

80%
Guziewicz M., Slysz W., Borysiewicz M., Kruszka R., Sidor Z., Juchniewicz M., Golaszewska K., Domagala J., Rzodkiewicz W., Ratajczak J., Bar J., Wegrzecki M., Sobolewski R.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 6A
A-76-A-79
EN
We report fabrication and characterization of ultrathin NbN and NbTiN films designed for superconducting photodetectors. Our NbN and NbTiN films were deposited on Al_2O_3 and Si single-crystal wafers by a high-temperature, reactive magnetron sputtering method and, subsequently, annealed at 1000°C. The best, 18 nm thick NbN films deposited on sapphire exhibited the critical temperature of 15.0 K and the critical current density as high as ≈ 8 × 10^6 A/cm^2 at 4.8 K.
6
Content available remote

Ion Beam Analysis of Hydrogen-Treated Ti/TiN Protective Nanomultilayers

80%
Kakuee O., Fathollahi V., Lamehi-Rachti M., Oliaiy P., Seyedi H., Safa S., Mojtahedzadeh Larijani M., Moazzami H.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 1
132-137
EN
Ti/TiN multilayer films with a few multilayer periods and a total sub-μm thickness were deposited on AISI 304 stainless steel substrates by ion coating deposition technique. To investigate the effect of hydrogen treatment on the corrosion behavior of the multilayers, some of the samples were hydrogen treated after deposition of the first and/or the second Ti interlayer. ^{14}N(d,α_1) ^{12}C nuclear reaction and the Rutherford backscattering spectrometry were used to obtain the atomic composition profiles and thickness of Ti/TiN layers. Nuclear reaction analysis confirmed the presence of two separable TiN layers of comparable thickness on the surface and in depth of the two-period multilayers. These techniques were used to determine the thickness of individual Ti and TiN layers and revealed that the stoichiometry of TiN layers was approximately Ti:N=1:1. Hydrogen depth profile in the prepared samples was obtained by elastic recoil detection analysis. It was found that a remarkable volume of hydrogen was uptaken by the Ti layer in the hydrogen treated samples. The TiN (200) diffraction peak in the X-ray diffraction pattern was observed with different intensities depending on the sample preparation parameters. The corrosion behavior of the multilayers was studied by means of potentiodynamic polarization in 0.5 M NaCl solutions. It was found that the hydrogen treatment of Ti interlayer could potentially improve the corrosion properties of the Ti/TiN layers.
7
Content available remote

Composition of Surface Layers Prepared by Ion Beam Assisted Deposition of Catalytic Metals from Pulsed Arc-Discharge Plasma onto Carbon Paper Substrates

80%
Poplavsky V., Luhin V., Koltunowicz T.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
295-298
EN
The layers were prepared by ion beam assisted deposition of iridium and platinum onto AVCarb® Carbon Fiber Paper P50 electrocatalyst supports for the production of diffusion layers of the membrane-electrode assemblies of low temperature fuel cells with polymer electrolyte membrane. Formation of the layers in the ion beam assisted deposition mode, by means of the deposition of metal and mixing of precipitating layer with the substrate by the accelerated (U=10 kV) ions of the same metal, was performed. In this process neutral fraction of metal vapour and ionized plasma of vacuum pulsed electric arc discharge were used. The investigations of morphology and composition of layers were carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, wave dispersive X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. It was established that the obtained catalytic layers contain atoms of the deposited metals and substrate material as well as impurity oxygen atoms. The surfaces contain also metal inclusions of several micrometer size which arise from the precipitation of deposited metal droplets from the arc discharge of an ion source. The content of iridium and platinum atoms in the layers is ≈2×10¹⁶ cm¯²; the concentration of the deposited metals equals about several atomic percent.
8
Content available remote

Ultrathin NbN Films for Superconducting Single-Photon Detectors

80%
Słysz W., Guziewicz M., Borysiewicz M., Domagała J., Pasternak I., Hejduk K., Rzodkiewicz W., Ratajczak J., Bar J., Węgrzecki M., Grabiec P., Grodecki R., Węgrzecka I., Sobolewski R.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 1
200-203
EN
We present our research on fabrication and structural and transport characterization of ultrathin superconducting NbN layers deposited on both single-crystal Al_2O_3 and Si wafers, and SiO_2 and Si_3N_4 buffer layers grown directly on Si wafers. The thicknesses of our films varied from 6 nm to 50 nm and they were grown using reactive RF magnetron sputtering on substrates maintained at the temperature 850°C. We have performed extensive morphology characterization of our films using the X-ray diffraction method and atomic force microscopy, and related the results to the type of the substrate used for the film deposition. Our transport measurements showed that even the thinnest, 6 nm thick NbN films had the superconducting critical temperature of 10-12 K, which was increased to 14 K for thicker films.
9
Content available remote

Changes in Amorphous Hydrogenated Carbon Films by Ultraviolet and Infrared Laser Irradiation

80%
Vinciūnaitė V., Grigonis A., Medvid A., Zabels R.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 5
874-876
EN
Amorphous hydrogenated carbon films were formed on the Si (100) wafers by a direct-ion beam deposition method from pure acetylene and acetylene-hydrogen gas mixtures. The films were irradiated with a nanosecond Nd:YAG laser working at the first harmonics (λ_1=1064 nm), the fourth harmonics (λ_4=266 nm) or with a Nd:YVO_4 laser working at the third harmonic (λ_3=355 nm). The films were studied by the Raman scattering, micro-Fourier transform infrared and Fourier transform infrared spectroscopies, null-ellipsometry, optical and scanning electron microscope, and Vickers hardness method. Irradiation by the wavelength λ_1=1064 nm leads to graphitization and formation of the silicon carbide, because of the silicon substrate decomposition. The samples were strongly modified after the irradiation by λ_3=355 nm - the thickness of the films decreased, and silicon carbide was formed. It was observed that nano-structured materials (e.g. carbon nano-onions, nc-diamond) were formed after the irradiation by λ_4=266 nm.
10
Content available remote

Ion Irradiation of Oxidized FeCoZr-CaF₂ Nanocomposite Films for Perpendicular Magnetic Anisotropy Enhancement

61%
Kasiuk J., Fedotova J., Przewoźnik J., Kapusta C., Skuratov V., Svito I., Bondariev V., Kołtunowicz T.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
206-209
EN
The paper is focused on the results of Xe ions irradiation of nanocomposite FeCoZr-CaF₂ films synthesized in the oxygen-containing atmosphere. Combined influence of nanoparticles partial oxidation and ion irradiation with different fluences on the crystalline structure, phase composition and magnetic anisotropy is analysed by X-ray diffraction, the Mössbauer spectroscopy and vibrating sample magnetometry. The origin of the detected progressive enhancement of perpendicular magnetic anisotropy as the result of films oxidation and irradiation is discussed in the context of formation of nanoparticles oxide shells and ion tracks along the films normal.
11
Content available remote

Ion-Induced Modification of Structure and Magnetic Anisotropy in Granular FeCoZr-CaF₂ Nanocomposite Films

61%
Kasiuk J., Fedotova J., Przewoznik J., Kapusta C., Skuratov V., Milosavljevic M., Bondariev V., Koltunowicz T.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
828-831
EN
The paper reports on the results of structural analysis and magnetometry of granular nanocomposite films FeCoZr-CaF₂ irradiated with Xe and Kr ions at different fluences. The observed effect of enhanced perpendicular magnetic anisotropy characterizing pristine films is discussed with respect to the irradiation regimes and structural changes of the films originating from the impact of ions.
12
Content available remote

Ion Beam Formation of Electrocatalysts for Direct Methanol and Ethanol Fuel Cells on the Basis of Carbon Catalyst Supports

51%
Poplavsky V., Dorozhko A., Luhin V., Matys V., Zukowski P., Czarnacka K.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
278-282
EN
Ion-beam modification of materials whose service properties are mainly controlled by the surface composition is of especial interest, in particular, for electrocatalysts, namely electrodes of fuel cells - perspective chemical current sources. A catalyst is needed for effective operation of fuel cell. In this paper active layers of the electrocatalysts were prepared by ion beam assisted deposition of catalytic (platinum) and activating (cerium) metals onto carbon (AVCarb® Carbon Fiber Paper P50 and Toray Carbon Fiber Paper TGP-H-060 T) catalyst supports. Formation of layers by ion beam assisted deposition by means of the deposition of metal and mixing of precipitating layer with the substrate by accelerated ions of the same metal, was carried out. Metal deposition and mixing between the precipitable layer and surface of the substrate by accelerated (U=10 kV) ions of the same metal were conducted from a neutral vapor fraction and plasma of vacuum arc discharge of a pulsed electric arc ion source. Study of the morphology and composition of layers was carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. According to the investigations with the use of cyclic voltammetry, the electrocatalysts with the prepared layers exhibited catalytic activity in the reactions of electrochemical oxidation of methanol and ethanol, which form the basis for the principle of operation of low temperature direct methanol and direct ethanol fuel cells.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.