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Wyszukujesz frazę "Wasik, D." wg kryterium: Autor


Tytuł:
Influence of iron nanowires oxidation on their semiconducting properties
Autorzy:
Krajewski, M.
Gołasa, K.
Wasik, D.
Powiązania:
https://bibliotekanauki.pl/articles/1160259.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Gf
62.23.Hj
61.46.Km
78.67.Uh
82.53.Mj
81.16.Pr
Opis:
The main aim of this work was to study the impact of thermal annealing on the structure of iron oxide shell covering iron nanowires in relation to their semiconducting properties. Studied nanomaterial has been produced via a simple chemical reduction in an external magnetic field and then it has been thermally-treated at 400°C, 600°C and also 800°C in a slightly oxidizing argon atmosphere. Annealed iron nanowires have been characterized by means of the Raman spectroscopy and photoluminescence in order to study the structure of iron oxide shell and its influence on semiconducting properties of the whole nanostructure. According to obtained experimental results, the composition of iron oxide shell covering the studied nanomaterial is changing with annealing temperature. The thermal treatment at 400°C leads to oxidation of iron coming from the core of nanomaterial and formation of a mixture of Fe₃O₄ and α -Fe₂O₃ on the surfaces of nanowires, while annealing at higher temperatures results in further oxidation of iron as well as the phase transformation of previously created Fe₃O₄ into the most thermodynamically stable form of iron oxide at ambient conditions - α -Fe₂O₃. This oxide has a major impact on the semiconducting properties of studied nanomaterial. Thereby, the measurements of photoluminescence enabled to estimate the bandgap of bulk and surface layer at about 1.8 eV and 2.1 eV, respectively.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-135-A-137
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pressure-Dependent Coupling of the $\text{}^{3}$A$\text{}_{2}$(F) and $\text{}^{1}$T$\text{}_{2}$(D) States of Ni$\text{}^{2+}$ in ZnS and ZnSe
Autorzy:
Wasik, D.
Baj, M.
Liro, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1886737.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
Opis:
We have investigated two close-lying $\text{}^{3}$A$\text{}_{2}$(F) and $\text{}^{1}$T$\text{}_{2}$(D) states of Ni$\text{}^{2+}$ impurity in ZnS and ZnSe. These states are strongly coupled to each other via the spin-orbit interaction and therefore, small variations of their energies induced by pressure have significantly changed absorption spectra related to them. In order to give a good interpretation to the experimental results we took into account the interaction between both states, their coupling to the lattice vibrations and the pressure-dependent separation between them.
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 319-322
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of measurement and reduction of the electromagnetic disturbances inducted by switching surges in LV circuits
Metoda pomiaru i redukcji zaburzeń elektromagnetycznych indukowanych przez przepięcia łączeniowe w obwodach nN
Autorzy:
Wąsik, Patryk D.
Powiązania:
https://bibliotekanauki.pl/articles/2070265.pdf
Data publikacji:
2021
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
EMI
circuit breaker
fast measurement method
LV circuits
wyłącznik nadprądowy
szybka metoda pomiarowa
obwody nN
Opis:
This paper presents a fast, reliable and portable method for measuring electromagnetic disturbances in LV circuits (overcurrent circuit breakers). The experiment was carried out under conditions reflecting the real measurement environment. The method was verified and confirmed by a series of measurements with passive components reducing the disturbance. The results of the measurements made it possible to obtain suitable EMI reduction solutions, which can be used to protect commutators or end consumers. The results obtained make it possible to apply the method to measurements of multichannel circuit breakers, in which measuring the turn-on time of individual channels is important for the correct operation of the devices.
W artykule przedstawiono szybką, niezawodną i przenośną metodę pomiaru zaburzeń elektromagnetycznych w obwodach nN (wyłączniki nadprądowe). Eksperyment przeprowadzono w warunkach odzwierciedlających rzeczywiste środowisko pomiarowe. Metoda została zweryfikowana i potwierdzona serią pomiarów z elementami pasywnymi redukującymi zaburzenia. Wyniki pomiarów pozwoliły na uzyskanie odpowiednich rozwiązań redukcji zaburzeń elektromagnetycznych. Dobrane komponenty mogą być wykorzystane do ochrony komutatorów lub odbiorników końcowych. Uzyskane wyniki pozwalają na zastosowanie metody do pomiarów wyłączników wielobiegunowych, w których pomiar czasu załączenia poszczególnych biegunów jest istotny dla poprawnej pracy urządzeń.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2021, 11, 4; 55--61
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrostatic Pressure Study of MBE CdMnTe Doped with Bromine
Autorzy:
Szczytko, J.
Wasik, D.
Przybytek, J.
Baj, M.
Waag, A.
Powiązania:
https://bibliotekanauki.pl/articles/1934026.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Gs
73.61.Ga
Opis:
We present Hall effect and resistivity measurements as a function of pressure performed on MBE-grown Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te (with x = 0.14) layer (1 μm) doped with bromine. The experimental data were analysed using positive and negative U model of the Br centres. We found that both models could reproduce the experimental points, but in the case of positive U model - only under assumption that the sample was completely uncompensated.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 933-936
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly Compensated GaAs Crystal Obtained by Molecular CO Doping
Autorzy:
Bożek, R.
Korona, K. P.
Nowak, G.
Wasik, D.
Słupiński, T.
Kaczor, P.
Powiązania:
https://bibliotekanauki.pl/articles/1929707.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
78.55.-m
78.20.Jq
Opis:
GaAs:C crystal was grown by liquid encapsulated Czochralski technique with large partial pressure of CO in ambient atmosphere p$\text{}_{CO}$/p$\text{}_{tot}$ = 0.2 and investigated using near and infrared absorption, photoluminescence, photoconductivity, photo-induced current transient spectroscopy and photo-Hall measurements. High resistivity of the crystal was found in electrical measurements (10$\text{}^{7}$ Ω cm, the Fermi level at 0.67 eV below conduction band at 300 K). Local vibrational mode revealed increased concentration of carbon acceptor and presence of oxygen related complexes. Photoluminescence spectra were dominated by two bands with peak energies at 1.49 eV and 0.8 eV. The near band gap emission shifts with excitation intensity up to 4 meV/decade. In photocurrent spectrum a strong photoionization band with E = 0.55 eV is observed.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 669-672
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MnAs Nanocrystals Embedded in GaAs
Autorzy:
Kwiatkowski, A.
Wasik, D.
Kamińska, M.
Twardowski, A.
Dłużewski, P.
Borysiuk, J.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1811951.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.-g
75.75.+a
Opis:
Magnetic properties of MnAs nanocrystals embedded in GaAs are analyzed in the frame of phenomenological model proposed by Sasaki for ferritin superparamagnets. Our calculations explain qualitatively experimental data of magnetization versus temperature, obtained according to zero-field-cooled and field-cooled protocols. They show dynamics of magnetization of MnAs nanocrystals in range of temperature from 10 K to 320 K. There is transition from state in which very slow dynamics is observed (frozen state) to state in which dynamics is fast (quasi-superparamagnetic state).
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1207-1211
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MnAs Nanocrystals Embedded in GaAs
Autorzy:
Kwiatkowski, A.
Borysiuk, J.
Bożek, R.
Wasik, D.
Kamińska, M.
Sadowski, J.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046925.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.+w
61.82.Fk
68.37.Rt
68.37.Lp
74.25.Ha
Opis:
We report on cross-sectional transmission electron microscopy and magnetic force microscopy studies performed on self-organized MnAs nanoclusters embedded in GaAs. It was found that 10÷20 nm large MnAs ferromagnetic nanocrystals were formed during rapid thermal annealing of Ga$\text{}_{1-x}$Mn$\text{}_{x}$As layers at 600ºC, leading to magnetic contrasts in magnetic force microscopy images.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 233-236
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Epitaxial Strain on Magnetic Anisotropy in (Ga,Mn)As
Autorzy:
Juszyński, P.
Wasik, D.
Gryglas-Borysiewicz, M.
Przybytek, J.
Szczytko, J.
Twardowski, A.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1403622.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.47.-m
Opis:
Two (Ga,Mn)As samples having different magnetic anisotropy (one with in-plane easy axis and another one with out-of-plane easy axis) were studied by means of magnetotransport experiments. Anisotropy field B_{A} was determined for both samples as a function of temperature. For the sample having in-plane easy axis, an inversion of the direction of planar Hall effect hysteresis was observed upon increase of temperature. This result was simulated using the Stoner-Wohlfarth model.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1004-1006
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Analysis of Magnetic Inclusions in Nanomaterials Based on Multiwall Carbon Nanotubes
Autorzy:
Brzózka, K.
Krajewski, M.
Małolepszy, A.
Stobiński, L.
Szumiata, T.
Górka, B.
Gawroński, M.
Wasik, D.
Powiązania:
https://bibliotekanauki.pl/articles/1032146.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.Qr
61.46.Fg
61.48.De
75.50.Tt
75.75.Cd
81.07.De
Opis:
Functionalized multiwall carbon nanotubes as well as nanocomposite based on that material covered by nanoparticles composed of iron oxides were the subject of investigations. In order to identify all iron-bearing phases including those reported on the base of previous X-ray diffraction measurements, the transmission Mössbauer spectroscopy was utilized. The experiments were carried out both at room temperature and also at low temperatures. It was stated that in the investigated nanotubes some impurities were present, originating from the catalyst remains, in form of Fe-C and α -Fe nanoparticles. The Mössbauer spectra collected for the nanocomposite showed a complex shape characteristic of temperature relaxations. The following subspectra related to iron-based phases were identified: sextet attributed to hematite, with hyperfine magnetic field reduced due to the temperature relaxations, sextet corresponding to iron carbide as well as two doublets linked to superparamagnetic hematite and ferrihydrites.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 863-865
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of thermal annealing on structure and oxidation of iron nanowires
Autorzy:
Krajewski, M.
Brzózka, K.
Górka, B.
Lin, W.-S.
Lin, H. -M.
Szumiata, T
Gawroński, M.
Wasik, D.
Powiązania:
https://bibliotekanauki.pl/articles/148838.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
amorphous iron and iron oxides
iron nanowires
Mössbauer spectroscopy
Raman spectroscopy
thermal annealing
Opis:
Raman spectroscopy as well as Mössbauer spectroscopy were applied in order to study the phase composition of iron nanowires and its changes, caused by annealing in a neutral atmosphere at several temperatures ranging from 200°C to 800°C. As-prepared nanowires were manufactured via a simple chemical reduction in an external magnetic fi eld. Both experimental techniques proved formation of the surface layer covered by crystalline iron oxides, with phase composition dependent on the annealing temperature (Ta). At higher Ta, hematite was the dominant phase in the nanowires.
Źródło:
Nukleonika; 2015, 60, 1; 87-91
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Physical Properties of SiC-GaAs Nano-Composites
Autorzy:
Kalisz, G.
Grzanka, E.
Wasik, D.
Świderska-Środa, A.
Gierlotka, S.
Borysiuk, J.
Kamińska, M.
Twardowski, A.
Pałosz, B.
Powiązania:
https://bibliotekanauki.pl/articles/2043724.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
07.35.+k
Opis:
Nano-composites consisting of primary phase of hard nanocrystalline SiC matrix and the secondary nanocrystalline semiconductor (GaAs) phase were obtained by high-pressure zone infiltration. The synthesis process occurs in three stages: (i) at room temperature the nanopowder of SiC is compacted along with GaAs under high pressure up to 8 GPa, (ii) the temperature is increased above the melting point of GaAs up to 1600~K and, the pores are being filled with liquid, (iii) upon cooling GaAs nanocrystallites grow in the pores. Synthesis of nano-composites was performed using a toroid-type high-pressure apparatus (IHPP of the Polish Academy of Sciences, Warsaw) and six-anvil cubic press (MAX-80 at HASYLAB, Hamburg). X-ray diffraction studies were performed using a laboratory D5000 Siemens diffractometer. Phase composition, grain size, and macrostrains present in the synthesized materials were examined. Microstructure of the composites was characterized using scanning electron microscopy and high resolution transmission electron microscopy. Far-infrared reflectivity measurements were used to determine built-in strain.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 717-721
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoluminescence Studies of GaN:Fe
Autorzy:
Niedźwiadek, A.
Wysmołek, A.
Wasik, D.
Potemski, M.
Szczytko, J.
Kamińska, M.
Twardowski, A.
Łucznik, B.
Pastuszka, B.
Grzegory, I.
Powiązania:
https://bibliotekanauki.pl/articles/2047373.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
71.55.Eq
71.20.Be
Opis:
We report on magneto-optical studies on iron doped GaN crystals grown using hydride vapor phase epitaxy method on bulk GaN substrate. The investigated samples showed an intensive 1.3 eV luminescence band, characteristic of Fe$\text{}^{3+}$(d$\text{}^{5}$) center in GaN. A high quality of the investigated samples allowed us to observe a well-resolved fine structure of intracenter transitions between $\text{}^{4}$T$\text{}_{1}$(G) and $\text{}^{6}$A$\text{}_{1}$(S) states, consisting of four sharp no-phonon lines. All the observed no-phonon lines showed pronounced splittings in magnetic field. From the analysis of the magneto-optical data, the structure of split $\text{}^{4}$T$\text{}_{1}$(G) multiplet in the magnetic field applied along c-axis of GaN crystals was established.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 177-182
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrared Spectroscopy of GaAs Doped with Mn
Autorzy:
Rutkowska, A.
Wasik, D.
Witowski, A.
Sadowski, M.
Orłowski, W.
Strzelecka, G.
Hruban, A.
Kamińska, M.
Twardowski, A.
Potemski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2044531.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ej
78.20.Ls
78.30.Fs
Opis:
We found that the fine structure related to Lyman spectra of [Mn$\text{}^{2+}$(d$\text{}^{5}$) + a hole] centers in GaAs was present only for samples with low Mn concentration. Such samples, at low temperature, did not show any hopping conductance within Mn impurity band. Magnetooptical measurements revealed that magnetic field induced splitting of the Lyman optical transitions was larger than Zeeman splitting observed for typical shallow acceptors in GaAs, like Be, Zn, and C. This experimental result proved that in the case of Mn acceptor impurity, the exchange coupling of a hole and the S = 5/2 Mn$\text{}^{2+}$(d$\text{}^{5}$) core could not be neglected, which was in accordance with the [Mn$\text{}^{2+}$(d$\text{}^{5}$) + a hole] model of the neutral Mn center in GaAs.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 845-849
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial Correlations of Donor Charges in MBE CdTe
Autorzy:
Suski, T.
Wiśniewski, P.
Litwin-Staszewska, E.
Wasik, D.
Przybytek, J.
Baj, M.
Karczewski, G.
Wojtowicz, T.
Zakrzewski, A.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1934021.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
71.55.Gs
Opis:
We present experimental evidence that at high pressures indium donors in CdTe localize electrons in spatially correlated manner. We have studied Hall mobility, μ$\text{}_{H}$, as a function of electron concentration, n$\text{}_{H}$, at T=77 K. Changes of n$\text{}_{H}$ have been achieved by two methods. High pressure freeze-out of electrons onto localized states of In-donors leads to the mobility enhancement with respect to the situation when n$\text{}_{H}$ has been modified by means of a subsequent annealing of the sample. As a result, depending on the degree of spatial correlations in the impurity charges arrangement, different values of μ$\text{}_{H}$ correspond to the same value of n$\text{}_{H}$. The variation of mobility with electron concentration suggests that the localized state of In-donor represents likely negatively charged DX state.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 929-932
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation of Mn-Related Defect Band in InP
Autorzy:
Macieja, B.
Korona, K. P.
Piersa, M.
Witowski, A. M.
Wasik, D.
Wysmołek, A.
Strzelecka, G.
Hruban, A.
Surma, B.
Palczewska, M.
Kamińska, M.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2036033.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
72.20.Ee
72.20.Jv
Opis:
Electron paramagnetic resonance, optical absorption, luminescence and electrical studies of InP highly doped with Mn were performed. Electron paramagnetic resonance revealed presence of manganese in Mn$\text{}^{2+}$(d$\text{}^{5}$) configuration. In optical absorption, systematic reduction of InP band gap was observed with increase in Mn content. This was correlated with increase in photoionization-type absorption band starting at 0.2 eV. Time-resolved photoluminescence measurements showed decrease in photoexcited carrier lifetime and shortening of donor-acceptor pair recombination time with increase in Mn content. Moreover, photoluminescence band was shifted to lower energies, similarly to optical band gap. In electrical transport two mechanisms of conductivity were observed. Valence band transport dominated at higher temperatures, above 160 K, and activation energy of free-hole concentration was determined as about 0.20 eV. At lower temperatures hopping conductivity, clearly related to Mn defect band, was present. All these results were consistent with assumption of creation of Mn-related defect-band at 0.2 eV above InP valence band. It was found that Mn centers responsible for this band were in configurations of either d$\text{}^{5}$ or d$\text{}^{5}$ plus a hole localized about 7Å around corresponding Mn core.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 637-642
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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