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Wyszukujesz frazę "61.72.-y" wg kryterium: Temat


Tytuł:
Charge Carrier Dynamics in $Ga_{1-x}Mn_{x}As$ Studied by Resistance Noise Spectroscopy
Autorzy:
Lonsky, M.
Teschabai-Oglu, J.
Pierz, K.
Sievers, S.
Schumacher, H.
Yuan, Y.
Böttger, R.
Zhou, S.
Müller, J.
Powiązania:
https://bibliotekanauki.pl/articles/1397018.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
73.50.Td
73.50.-h
73.61.-r
64.60.ah
61.72.-y
Opis:
We report on electronic transport measurements of the magnetic semiconductor Ga_{1-x}Mn_{x}As, whereby the defect landscape in various metallic thin films (x=6%) was tuned by He-ion irradiation. Changes in the distribution of activation energies, which strongly determine the low-frequency 1/f-type resistance noise characteristics, were observed after irradiation and can be explained by deep-level traps residing in the As sublattice. Various other kinds of crystalline defects such as, for instance, Mn interstitials, which possibly form nanoscale magnetic clusters with a fluctuating spin orientation, also contribute to the 1/f noise and can give rise to random telegraph signals, which were observed in films with x=7%. In addition, we neither find evidence for a magnetic polaron percolation nor any features in the noise near the Curie temperature.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 520-522
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Losses Evolution of Ferritic Fe-Si Steel Subjected to Temper Rolling at Elevated Temperature
Autorzy:
Petryshynets, I.
Kováč, F.
Falat, L.
Puchý, V.
Šebek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030935.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
75.50.Vv
81.40.Ef
61.72.Cc
Opis:
The effects of heat transport phenomena and deformation gradient through the sheet cross-section on the microstructure, texture and magnetic properties of non-oriented Fe-Si steel were investigated. In order to achieve desired conditions for the steel microstructural and textural parameters improvement, a temper rolling process at elevated temperature was examined in combination with subsequent short term annealing, employing fast heating rate in laboratory conditions. The experimental material was represented by conventional medium silicon, vacuum degassed non-oriented steel that was taken directly from industrial line after final annealing. Performed electron back scattered diffraction measurements revealed that the experimental steel, treated by our proposed thermomechanical treatment, was characterized by coarse-grained microstructure with enhanced intensity of rotating cube texture. The magnetic losses of experimental samples were measured in ac magnetic field with 50 Hz frequency on the toroid with external and internal diameters of 25 mm and 15 mm, respectively. These measurements with magnetic field intensity of 2500 A/m showed that the application of our suggested treatment led to clear power losses reduction of the investigated material from initial 9.9 W/kg to 6.4 W/kg, i.e. by more than 35%.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 1065-1068
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of Intrinsic Defects in CaYAl₃O₇
Autorzy:
da C. Bispo, G.
Jackson, R.
Valerio, M.
Powiązania:
https://bibliotekanauki.pl/articles/1029677.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Bn
61.72.-y
34.20.Cf
Opis:
CaYAl₃O₇ presents a challenge for computer modelling techniques because of its site-occupancy disorder related to the Ca/Y shared site. Supercells were built to reproduce experimental results which have the best agreement and lowest lattice energy. The potential parameters were obtained by empirical fitting, and reproduced the structure to within 1.09%. Results obtained by supercell and the Mott-Littleton methods were compared. Both methods predict oxygen Frenkel defects are likely to be formed.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 781-784
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Origin of point defects in β-Ga₂O₃ single crystals doped with Mg²⁺ ions
Autorzy:
Luchechko, A.
Vasyltsiv, V.
Kostyk, L.
Tsvetkova, O.
Powiązania:
https://bibliotekanauki.pl/articles/1052715.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
78.20.-e
72.40.+w
Opis:
Optical absorption and photoconductivity investigations of nominal pure and Mg²⁺ doped β-Ga₂O₃ single crystals have been carried out. Additional bands in the UV (3.6-4.6 eV) and near-IR (0.4-1.2 eV) spectral regions were found in optical absorption and photoconductivity spectra. A correlation between Mg²⁺ doping, annealing in oxygen atmosphere as well as optical absorption and photoconductivity bands were established in gallium oxide. Electronic transitions from shallow traps and F-centers were observed in the IR spectral region (0.4-1.2 eV). Absorption and photoconductivity in the UV region are related to deep acceptor levels created by native defects and impurities.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 811-815
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ORR Electrocatalysis on Cr³⁺, Fe²⁺, Co²⁺-Doped Manganese(IV) Oxides
Autorzy:
Sokolsky, G.
Zudina, L.
Boldyrev, E.
Miroshnikov, O.
Gauk, N.
Kiporenko, O.
Powiązania:
https://bibliotekanauki.pl/articles/1030872.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Fn
61.72.-y
85.40.Ry
Opis:
The ionic dopant additives have different mechanisms of their influence upon MnO₂ electrocrystallisation process and depending on dopants added the following polymorphs are stabilised: α -MnO₂ (hollandite, I4/m) - NH₄⁺; γ -MnO₂ (ramsdellite, Pbnm) - Co²⁺, Fe²⁺; layered polymorph δ -MnO₂ (birnessite, C2/m) - Cr³⁺. The defect states of intergrowth method in ramsdellite matrix and twinning, OH groups studied by X-ray diffraction and the Fourier transform infrared mtehod, respectively, indicate their high content in case of Fe²⁺ and Co²⁺-doped manganese dioxide. CVA oxygen reduction reaction peaks were established after experiments in alkaline electrolytes and dioxygen (argon, air) atmosphere. Activity of doped samples studied is comparable with other published data. Both doped with Co²⁺ and Fe²⁺ samples display maximal currents and some distinctive features in oxygen reduction reaction.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 1097-1102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Defects in Titanium Created by Hydrogen Charging
Autorzy:
Hruška, P.
Čížek, J.
Knapp, J.
Melikhova, O.
Havela, L.
Mašková, S.
Lukáč, F.
Powiązania:
https://bibliotekanauki.pl/articles/1033958.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.72.-y
Opis:
Hydrogen interaction with vacancies in α-Ti was investigated employing positron lifetime spectroscopy combined with ab initio theoretical modeling of vacancy-hydrogen complexes. Ab initio modeling revealed that multiple hydrogen atoms up to 7 can be trapped at vacancies in the α-Ti lattice. Trapped H atoms are located close to the nearest neighbor tetrahedral sites around the centre of vacancy. Lifetimes of positrons trapped at vacancies associated with various numbers of hydrogen atoms were calculated. Positron lifetime measurement of H-loaded α-Ti samples revealed that phase transition into the hydride phase introduced dislocations. Vacancies were created by H loading as well and agglomerated into small vacancy clusters.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1606-1610
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Laser Scribing on Soft Magnetic Properties of Conventional Grain-Oriented Silicon Steel
Autorzy:
Petryshynets, I.
Puchý, V.
Kováč, F.
Šebek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032233.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
79.20.Eb
68.55.jm
77.80.Dj
75.50.Vv
Opis:
The present work investigates the influence of laser scribing of grain-oriented silicon steel on the improvement of its soft magnetic properties via magnetic domains modification. The experimental material was represented by conventional Fe-3%Si grain-oriented electrical steel that was taken directly from industrial line after the final box annealing. The laser scribing treatments were applied onto the material surface in order to induce thermal stresses having crucial influence on the magnetic domains refinement. The laser scribing conditions have been optimized by introducing thermal stresses onto the experimental material surface leading to optimal refinement of final domains structures and desired magnetic softness minimization. A semiquantitative relationship has been found between the domain patterns and the used fiber laser treating method. The obtained modified domain structure led to a significant decrease in coercivity measured in DC magnetic field from 20 A/m to 12 A/m.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 777-779
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetic Resonance in CdTe:Cr Single Crystals Containing Dopant-Related Macrodefects
Autorzy:
Popovych, V.D.
Kuzma, M.
Skop, N.
Stefaniuk, I.
Cieniek, B.
Powiązania:
https://bibliotekanauki.pl/articles/1030219.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
68.37.Hk
76.50.+g
Opis:
We study CdTe:Cr single crystals grown by the physical vapor transport method from pre-synthesized (Cd,Cr)Te alloys with 5 at.% of chromium nominal content. Macrodefects in the form of (111)-oriented thin platelets of dopant-related second phases were detected by scanning electron microscopy patterning of the chemically treated surfaces of the crystals. Magnetic properties of the crystals were investigated by ferromagnetic resonance using X-band Bruker spectrometer (9.43 GHz). Their ferromagnetic resonance spectra show several broad lines, which position depends on the orientation of the sample in relation to the external magnetic field in spectrometer. The angular dependences of ferromagnetic resonance spectra are interpreted in the frame of shape anisotropy of ferromagnetic resonance of the planar defects embedded in a weak magnetic CdTe matrix.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 34-38
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Impulse Shot Peening Parameters on Properties of Stainless Steel Surface
Autorzy:
Wiertel, M.
Zaleski, K.
Gorgol, M.
Skoczylas, A.
Zaleski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1033967.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.65.-b
81.20.Wk
62.20.Qp
61.72.-y
78.70.Bj
Opis:
Shot peening was applied to austenitic stainless steel 1.4541 (EN). The surface treatment was performed at various impact energies E, impact densities j and ball diameters D. This resulted in improved microhardness, which increases monotonically with the increase of E, j and 1/D. However, its changes with E and j achieve saturation at about 400 HV0.1. On the contrary, no saturation is observed in the investigated range for 1/D. In the un-shot peened 1.4541 (EN) steel, the lifetime component of low intensity was found with use of positron annihilation lifetime spectroscopy (PALS). It corresponds to positron annihilation from delocalized state of positrons in bulk. In the shot peened samples the bulk component is no longer observed. Instead, two types of defects can be identified: vacancy-like defects coupled with edge dislocations and vacancies or their small clusters (consisting 3÷5 vacancies). The results of PALS and hardness testing do not correspond very well, especially in the case of the samples shot peened with balls of varying diameters. The most probable reason for this are different depth profiles of both methods. It seems that the defects, which are responsible for the increase of static microhardness above 400 HV0.1 are located mostly below the surface layer penetrated by positrons.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1611-1615
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of spark plasma sintering on microstructure and properties of bulk LaCaSrMnO magnetocaloric materials
Autorzy:
Zmorayová, K.
Antal, V.
Kováč, J.
Diko, P.
Noudem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1053176.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
61.72.-y
75.30.Kz
77.80.B-
81.70.Pg
81.20.Ev
81.30.Fb
Opis:
Polycrystalline La_{0.67}Ca_{0.33-x}Sr_xMnO₃ (x=0.33, 0.03, 0) (LCSM) perovskite samples treated by spark plasma sintering technique were investigated. This study proved influence of the sintering temperature on microstructure of these perovskite ceramics. The thermogravimetric measurements revealed the possibility of increase of oxygen content in studied LCSM samples by additional annealing under oxygen atmosphere and low temperature. Finally, the effect of this annealing on magnetic properties was demonstrated.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 804-806
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Thermal Processing in High Magnetic Field on Soft Magnetic Properties and Crystallographic Texture of Non-Oriented Fe-Si Steels
Autorzy:
Petryshynets, I.
Kováč, F.
Marcin, J.
Škorvánek, I.
Powiązania:
https://bibliotekanauki.pl/articles/1032640.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
61.72.-y
68.55.jm
75.60.Nt
75.50.Vv
Opis:
In this work, we report on the effects of high static magnetic field on the formation of desirable crystallographic orientation of grains ("rotating" cube) during the primary recrystallization of non-oriented steels. Vacuum degassed non-oriented steel with the silicon content about 1 wt% was taken from industrial line after final cold rolling with 80% of deformation and then it was subjected to the laboratory annealing at temperature of primary recrystallization. Whole annealing process was carried with and without the applied external magnetic field of 14 T. The analysis of crystallographic orientation of experimental material was studied by electron backscattered diffraction technique. The microstructural and textural observations have shown a small difference in average grain size between samples annealed with and without magnetic field as well as increase of the "rotating" Cube component and decrease of the intensity of deformation texture by application of magnetic field. The magnetic measurements show that the coercivity value of the sample annealed in the magnetic field of 14 T can be reduced by approximately 3% in comparison with sample annealed under the zero field conditions.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 783-785
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local Pseudoelastic Behaviour and Surface Characteristics of N Ion Implanted NiTi Shape Memory Alloy
Autorzy:
Levintant-Zayonts, N.
Kwiatkowski, L.
Swiatek, Z.
Brzozowska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1030131.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.fg
81.40.Jj
61.72.U-
61.72.-y
Opis:
The main goal of the proposed paper is to present the results of the nitrogen ion implantation effects on mechanical and corrosion properties of NiTi shape memory alloy. Local pseudoelasticity phenomena of NiTi were determined using the ultra-low load applied system. The load-penetration depth curves show that lower nitrogen fluence improves mechanical properties in the near surface layer but higher ion fluence leads to degradation of pseudoelasticity properties. Corrosion resistance of NiTi in the Ringer solution was evaluated by means of electrochemical methods. The results of potentiodynamic measurements in the anodic range for implanted NiTi indicate a decrease of passive current density range in comparison with non-treated NiTi, without any signs related to Ni release. The results of impedance measurements recorded at the corrosion potential show a capacitive behaviour for all samples without clear predominance of one of them. It can be explained by the fact that this result concerns the first stage of corrosion exposition. It is shown that nitrogen ion implantation leads to formation of modified surface of improved physicochemical properties.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 210-216
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of Sm addition on the microstructure and superconducting properties of YBCO bulk superconductors
Autorzy:
Volochová, D.
Diko, P.
Piovarči, S.
Antal, V.
Kováč, J.
Jirsa, M.
Powiązania:
https://bibliotekanauki.pl/articles/1054772.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.62.Dh
81.10.Fq
61.72.-y
74.25.Ha
74.25.Sv
Opis:
The effect of Sm addition on the microstructure and superconducting properties of Y-Ba-Cu-O (YBCO) bulk superconductors has been studied. Nominal composition: 1 mol YBa₂Cu₃O_{7-δ} + 0.25 mol Y₂O₃ + 1 wt% CeO₂ was enriched with different amounts of SmBa₂Cu₃O_y powder with the aim to increase critical current density, J_c, especially in higher magnetic fields by introducing additional pinning centers. Single grain YBCO bulk superconductors with SmBa₂Cu₃O_y (Y123-Sm) addition were prepared by the optimized top seeded melt growth process. Microstructure analysis, performed by polarized light microscope, revealed that SmBa₂Cu₃O_y addition leads to a higher amount of slightly coarser Y₂BaCuO₅ particles, which is related to lower critical current densities (J_c ≈ 6×10⁴ A/cm²) of the YBCO samples with SmBa₂Cu₃O_y addition in low magnetic fields. On the other hand, an enhancement of critical current density, J_c, in higher magnetic fields was observed for Y123-Sm samples. Moreover, a maximum trapped magnetic field, B_{tmax}, of 564 mT at 77 K in Y123-Sm, x=0.0025 sample (Ø 17.2 mm) was 43% higher than that for YBCO sample without any addition.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1009-1011
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ab Initio Investigation on the Effect of Transition Metals Doping and Vacancies in WO₃
Autorzy:
Mansouri, M.
Mahmoodi, T.
Powiązania:
https://bibliotekanauki.pl/articles/1398658.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.A-
61.72.-y
71.15.Mb
71.15.Dx
Opis:
We did a density functional theory spin-polarized calculation based on pseudopotential method on the effect of both vacancy and substitutional impurity in the tungsten tri-oxide lattice. We investigated oxygen and tungsten vacancies and for substitutional dopants we used palladium (Pd), platinum (Pt) and gold (Au) atoms with the formula $A_xW_{1-x}O_3$ and x=0.125, 0.25, 0.375, 0.5. We obtained electronic band structure, density of states and magnetization of defected and doped WO₃. The results show that in the presence of tungsten vacancy, WO₃ acts as a semiconductor with an indirect band gap while oxygen vacancy induces a metallic behavior for WO₃. Besides, for Pt and Pd the location of trap states lead to photoexcited hole capturing, which can improve photocurrent but for Au dopant, the trap states occur in the middle of the band gap as active recombination centers. Furthermore, both kind of vacancies and Pt dopant can induce magnetization in all values of x, while Pd and Au are less efficient in inducing magnetization.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 8-14
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boriding of binary Ni-Ti and ternary Ni-Ti-Cu shape memory alloys
Autorzy:
Ucar, N.
Turku, N.
Ozdemir, A.
Calik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1065676.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Dk
61.72.-y
62.20.Qp
Opis:
In this work, the boriding of binary (Ni-Ti) and ternary (Ni-Ti-Cu) shape memory alloys was carried out in a solid medium at 1173 K for 8 h using the powder pack method with Ekabor-Ni powders. Characterization of boride layer formed on the surface of alloys was identified by optical microscopy and scanning electron microscopy. TiB₂, NiB₂ and SiC phases in the boride layer of borided binary (Ni-Ti) and ternary (Ni-Ti-Cu) shape memory alloys was confirmed by X-ray diffraction analysis. The microhardness and thickness of the boride layers were measured. The obtained hardness values show a hardness anomaly due to porosity and structural defects with increase of Cu content, while a decrease in the value of hardness moving from the boride layer to main structure was observed.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 492-495
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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