Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Kozlowski, A." wg kryterium: Autor


Tytuł:
Magnetite Fe$\text{}_{3}$O$\text{}_{4}$: the Correlated Electron-Phonon System
Autorzy:
Kozłowski, A.
Kąkol, Z.
Tarnawski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2047312.pdf
Data publikacji:
2007-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Kb
75.40.-s
63.20.Kr
71.30.+h
75.30.Cr
Opis:
In the paper the influence of magnetic as well as electron-lattice interactions on the Verwey transition in magnetite related compounds is discussed based on the authors' experimental activity and available literature. While magnetism was proved to only reflect the transition, the results of nuclear inelastic scattering show that lattice dynamics actively participates in it. The studies of diffuse neutron scattering and heat capacity suggest also that the low temperature lattice properties of slightly doped magnetite are distinct from those with higher dopant concentration. Finally, recent theoretical results strongly suggest that the Verwey transition in magnetite cannot be understood and described without strong involvement of electron-lattice interactions.
Źródło:
Acta Physica Polonica A; 2007, 111, 4; 537-547
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific Heat and Magnetoresistance of Y-, Tl- and Bi-Type High-Temperature Superconductors
Autorzy:
Zalecki, R.
Kozłowski, A.
Kołodziejczyk, A.
Gritzner, G.
Mair, M.
Powiązania:
https://bibliotekanauki.pl/articles/1955838.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.Fq
74.25.Ha
74.72.Bk
74.72.Hs
74.25.Bt
Opis:
Specific heat of polycrystalline DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ and Tl$\text{}_{0.58}$Pb $\text{}_{0.42}$Sr$\text{}_{1.6}$Ba$\text{}_{0.4}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{9}$ samples, as well as the single crystal of Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8}$ have been measured within the temperature interval from 50 to 250 K. For Dy- and Tl-specimens the pronounced jump in specific heat and apparent contribution from Gaussian fluctuations of superconducting order parameter close to T$\text{}_{c}$ have been observed. In contrary, for Bi-specimen only a rounded maximum within a broad interval around T$\text{}_{c}$ has been detected. Magnetoresistance measurements as a function of temperature just below T$\text{}_{c}$ have been carried out for Dy- and Tl-samples and the slopes of upper critical fields have been determined. The data have been analysed within a frame of Ginzburg-Landau-Abrikosov- Gorkov theory with additional Gaussian-like fluctuation term. The electronic specific heat coefficients γ, and the coherence length χ have been obtained.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 431-434
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rhombohedral Distortion in Fe$\text{}_{3-y}$Zn$\text{}_{y}$O$\text{}_{4}$ at Verwey Transition
Autorzy:
Kozłowski, A.
Kąkol, Z.
Zalecki, R.
Knight, K.
Honig, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1955841.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
64.70.Kb
61.12.-q
Opis:
The time-of-flight neutron diffraction data were collected for two Fe$\text{}_{3-y}$Zn$\text{}_{y}$O$\text{}_{4}$ powder samples showing different order of the Verwey transition: y=0.0072 - first order, y=0.0249 - second order. Measurements were performed on spallation neutron source in ISIS Rutherford Appleton Laboratory. At low temperatures (below Verwey transition temperature T$\text{}_{V}$) clear splitting of certain reflections characteristic of rhombohedral distortion was observed for both samples. We found that this distortion is much bigger for the sample exhibiting first-order than for the sample showing second-order transition.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 443-446
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cation Distribution in Fe$\text{}_{3(1-\delta)}$O$\text{}_{4}$ and Low Level Doped Fe$\text{}_{3-x}$M$\text{}_{x}$O$\text{}_{4}$, M=Ti, Zn, Al
Autorzy:
Kąkol, Z.
Kozłowski, A.
Sabol, J.
Metcalf, P.
Honig, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1861287.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ga
75.30.Cr
75.50.Gg
Opis:
Systematic magnetic saturation moment and electrical resistivity measurements of the Fe$\text{}_{3(1-\delta)}$O$\text{}_{4}$ and Fe$\text{}_{3-x}$M$\text{}_{x}$O$\text{}_{4}$ (M = Ti, Zn, Al) are presented. Cation distributions for low level doping are proposed and compositional dependencies of the Verwey transition temperature are determined. The latter show striking similarities in their dependence on cation vacancies and dopant concentration for any extraneous cations. These data are the basis for the analysis of the correlation between the presented cations distributions and the Verwey transition.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 223-227
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Band Structure and Photoemission States of $Bi_{1.96}Mg_{0.04}Se_3$
Autorzy:
Tokarz, W.
Zalecki, R.
Kowalik, M.
Kołodziejczyk, A.
Kozłowski, A.
Miotkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1374118.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.55.Ak
72.80.Ga
75.47.Lx
79.60.-i
Opis:
We present theoretical band structure calculations and ultraviolet electron photoemission spectroscopy of a topological insulator $Bi_{1.96}Mg_{0.04}Se_3$. Our calculations were based on the first-principles density functional theory with general gradient approximation using Wien2k package with the spin-orbit interaction included by a second-variation method. The R3̅m crystal structure was optimized. In consequence, 4% decrease of volume and 3% decrease of ratio c/a was obtained. This modified structure was multiplied three times in a and b direction in order to place proper amount of Mg. Final crystal structure P3m1 with 135 atoms was used for the calculations. As a result metallic band structure was obtained with conduction band extended from -5.6 eV up to 0.16 eV. It composes mostly from Se p states. Comparison of total DOS with ultraviolet photoemission spectrum shows similar features.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-127-A-129
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of the Magnetic Axis Switching in Magnetite
Autorzy:
Król, G.
Kusz, J.
Tarnawski, Z.
Kąkol, Z.
Tabiś, W.
Kozłowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046773.pdf
Data publikacji:
2006-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
61.50.Ks
75.30.Gw
Opis:
The influence of the external magnetic field on magnetic and crystallographic structure of magnetite was studied. We have confirmed, by means of vibrating sample magnetometer measurements, that external magnetic field can switch the easy magnetic axis to the new crystallographic direction. We have also proved by the direct observation of the crystalline structure that this phenomenon is strictly related to the crystallographic structure relaxation.
Źródło:
Acta Physica Polonica A; 2006, 109, 4-5; 601-605
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Properties of High-Temperature Superconductor DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ from Critical Fields and Specific Heat Studies
Autorzy:
Kołodziejczyk, A.
Kozłowski, A.
Chmist, J.
Zalecki, R.
Ściężor, T.
Tarnawski, Z.
Woch, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/1929388.pdf
Data publikacji:
1993-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.70.-b
76.30.-v
Opis:
The lower and upper critical fields, as well as the specific heat were measured as a function of temperature for good quality DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ high-temperature superconductor in the vicinity of superconducting transition temperature T$\text{}_{c}$ = 91.2 K. The number of superconducting and normal state electronic quantities were determined basing on the Ginzburg-Landau-Abrikosov-Gorkov theory. It is argued that on the basis of this BCS-like theory one can describe the superconducting properties and, in combination with some information on the electronic structure, also the magnetic properties of high-temperature superconductors.
Źródło:
Acta Physica Polonica A; 1993, 84, 1; 127-138
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Capacity and Elastic Constants of Fe$\text{}_{3-x}$Zn$\text{}_{x}$O$\text{}_{4}$ in the Vicinity of the Verwey Transition
Autorzy:
Kozłowski, A.
Kąkol, Z.
Schwenk, H.
Bareiter, S.
Hinkel, C.
Luthi, B.
Honig, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2013722.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.Dc
63.20.-e
64.60.-i
65.40.+g
Opis:
The results of the heat capacity and elastic constant studies of Fe$\text{}_{3-x}$Zn$\text{}_{x}$O$\text{}_{4}$ (x<0.04) series are reported. Adiabatic heat capacity measurements, performed on single crystals, show the clear change of the transition character from first order for low Zn content (x<0.012) to the higher order in 0.012
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 883-887
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of the Verwey Transition in Magnetite
Autorzy:
Tarnawski, Z.
Wiecheć, A.
Madej, M.
Nowak, D.
Owoc, D.
Król, G.
Kąkol, Z.
Kolwicz-Chodak, L.
KozŁowski, A.
Dawid, T.
Powiązania:
https://bibliotekanauki.pl/articles/2041527.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.18.Bn
75.40.-s
71.20.Lp
Opis:
Studies of the specific heat and simultaneous AC magnetic susceptibility (ρ') and electric resistance of stoichiometric magnetite single crystal are presented. The temperature hysteresis of the Verwey transition is of 0.03 K found from the specific heat data confirming its first-order character. The continuous temporal change of ρ' at T$\text{}_{V}$ can be switched off by an external magnetic field without affecting the transition. The electrical resistance decreases continuously with increasing temperature with a rapid change of slope at the point when the phase transition is completed. It was concluded that the magnetic degrees of freedom do not actively participate in the transition and that the entropy released at T$\text{}_{V}$ may come from ordering electrons.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 771-775
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemically Modified Activated Carbons as Catalysts of Oxidative Dehydrogenation of n-Butane
Autorzy:
Malaika, A.
Wower, K.
Kozłowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1535911.pdf
Data publikacji:
2010-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Rm
81.65.Mq
81.40.Gh
82.65.+r
Opis:
Commercial availability and low price of light alkanes make them very attractive in many branches of industry. Potentially interesting is their use in the process of oxidative dehydrogenation leading to production of olefins. This study was undertaken to characterise the oxidative dehydrogenation of n-butane to 1,3-butadiene (important substrate in production of synthetic rubber and polyamides) taking place over the modified carbon catalysts obtained from peach stones precursor. The catalytic tests were performed in the temperature range 250-450°C at oxygen/n-butane ratio of 1:1. For the majority of the activated carbon samples studied at the lowest temperature the only product was $CO_2$. At 300°C the products of dehydrogenation of n-butane and side products appeared. With increasing temperature the amount of compounds generated increased and in the group of C4 hydrocarbons the dominant were 1-butene and 1,3-butadiene. The most effective catalyst was the sample oxidised with air, the least effective was the sample modified with ammonium peroxydisulphate.
Źródło:
Acta Physica Polonica A; 2010, 118, 3; 459-464
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluorescence of Sodium Vapour Excited by 330 nm Laser Pulses
Autorzy:
Gorbunov, N. A.
Kozłowski, P.
Nowak, K.
Stacewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/2025779.pdf
Data publikacji:
2001-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.80.Wr
34.80.Dp
46.65.+g
Opis:
We report results of investigation on the fluorescence induced in sodium vapour by pulses of laser light tuned near the 3S → 4P transition (330 nm). The fluorescence was observed in perpendicular and parallel directions in respect to the laser beam. A depletion of fluorescence intensity corresponding to the 5D → 3P transition (498 nm) was observed along the laser beam. We explain this effect as a result of reabsorption that is caused by intense population of the 3P level due to cascade stimulated processes. The most intense depletion occurs about 20 ns after the laser pulse and it corresponds to the moment of maximal population of the 3P level.
Źródło:
Acta Physica Polonica A; 2001, 99, 5; 531-537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR characteristics of activated carbon for hydrogen production by the thermo-catalytic decomposition of methane
Autorzy:
Więckowski, A.
Najder-Kozdrowska, L.
Rechnia, P.
Malaika, A.
Krzyżyńska, B.
Kozłowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1158900.pdf
Data publikacji:
2016-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.35.+r
61.66.Hq
76.30.-v
82.30.Lp
82.65.+r
88.30.ej
Opis:
The electron paramagnetic resonance (EPR) method was used to characterize samples of activated coal before and after reactions of the catalytic decomposition of methane and ethanol at temperatures of 1023 K (750°C), 1123 K (850°C) and 1223 K (950°C). The EPR parameters: spectroscopic splitting factor g, peak-to-peak linewidth ΔBₚₚ, and spin concentration c were measured. During the ethanol-assisted catalytic decomposition of methane carbon-located-spin radicals are partially transformed into oxygen-located-spin radicals.
Źródło:
Acta Physica Polonica A; 2016, 130, 3; 701-704
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Groups of Paramagnetic Centres in Reduced and Methylated Low Rank Coal
Autorzy:
Pilawa, B.
Wachowska, H.
Kozłowski, M.
Więckowski, A.
Najder-Kozdrowska, L.
Powiązania:
https://bibliotekanauki.pl/articles/1401865.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.35.+r
61.66.Hq
76.30.-v
76.30.Rn
89.30.ag
Opis:
Low rank Illinois No. 6 coal was studied by electron paramagnetic resonance EPR spectroscopy. The parameters of EPR spectra (spectroscopic splitting factors g, linewidths $\DeltaB_{pp}$, concentrations of paramagnetic centres N) were measured for row and chemically treated coal (demineralized, reduced and methylated samples). The multi-component structure of experimental spectra of this coal was proved. Two groups of paramagnetic centres responsible for broad Lorentzian 1 and narrow Lorentzian 2 lines exist in studied samples. Paramagnetic centres connected with component lines revealed different behaviour during chemical treatments.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 264-267
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy, Geometric Structure and Frustration Effects in Molecule-Based Nanomagnets
Autorzy:
Kamieniarz, G.
Kozłowski, P.
Antkowiak, M.
Sobczak, P.
Ślusarski, T.
Tomecka, D.
Barasiński, A.
Brzostowski, B.
Drzewiński, A.
Bieńko, A.
Mroziński, J.
Powiązania:
https://bibliotekanauki.pl/articles/1426672.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
75.10.Jm
75.10.Pq
75.40.Cx
Opis:
In this paper we review our results of comprehensive study of molecular nanomagnets recently synthesized in the form of the chromium-based molecules and bimetallic copper-containing chains as well as we present some new findings. We focus on effects of anisotropy, geometry and frustration appearing in various thermodynamic properties of the nanoscale magnets which are described by Heisenberg-like spin models and simulated by accurate numerical methods. We show that bond-dependent exchange anisotropy is needed to model magnetic torque in the Cd-doped chromium ring. We argue that only in the limit of infinite rings (n → ∞) frustration can be considered as the opposite to bipartiteness in the odd numbered (3 ≤ n ≤ 9) s = 3/2 quantum spin rings. We analyse the influence of exchange interactions and anisotropy on magnetic susceptibility of bimetallic (S = 3/2, s = 1/2) chains composed of Cu ions linked to different 3d ions by fitting experimental data. We reach the remarkable consistency of the density functional theory estimates of the magnetic couplings in $Cr_8$ molecule and provide strong support to the spin models exploited in the literature.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 992-998
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Microscopy and X-ray Structural Investigations of Incommensurate Spin-Ladder Sr$\text{}_{4.1}$Ca$\text{}_{4.7}$Bi$\text{}_{0.3}$Cu$\text{}_{17}$O$\text{}_{29}$ Single Crystals
Autorzy:
Dłużewski, P.
Pietraszko, A.
Kozłowski, M.
Szczepańska, A.
Górecka, J.
Baran, M.
Leonyuk, L.
Babonas, G.-J.
Lebedev, O.
Szymczak, R.
Powiązania:
https://bibliotekanauki.pl/articles/2014560.pdf
Data publikacji:
2000-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Nn
61.72.Mm
74.72.-h
61.16.Bg
61.10.-i
Opis:
Transmission electron microscopy and X-ray diffraction proved chain ladder incommensurate single crystal structure of investigated samples. The incommensurate ratio was determined from the X-ray and electron diffraction being equal to 0.704. Diffuse scattering intensities localised on the planes perpendicular to the c*-axis and passing through the spots originating from the periodicity of chain sublattice were detected. High-angle grain boundary or twinning formed by rotation of 33.3° around [100] direction was observed. High-resolution electron microscopy images revealed the stacking faults in ac planes.
Źródło:
Acta Physica Polonica A; 2000, 98, 6; 729-737
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies