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Wyszukujesz frazę "Dobrowolski, M." wg kryterium: Wszystkie pola


Tytuł:
Low-Frequency Raman Spectrum οf Bulk $Zn_{0.984}Co_{0.016}O$ Crystal
Autorzy:
Szuszkiewicz, W.
Łusakowski, A.
Morhange, J.
Gołacki, Z.
Arciszewska, M.
Brodowska, B.
Kanehisa, M.
Klepka, M.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1807848.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
The influence of possible presence of $Co^{2+}$ ion pairs in a bulk $Zn_{1-x}Co_{x}O$ mixed crystal on the low-frequency part of the Raman spectrum is discussed. Two effects can be taken into account in the theoretical considerations when analyzing the energy level scheme corresponding to Co ions. The first is a local lattice deformation in the vicinity of $Co^{2+}$ ion due to a presence of the second ion, smaller than the host ZnO lattice cation. Such deformation creates a trigonal field, which can only slightly modify the energy levels of $Co^{2+}$ ion. The second effect, which results from an antiferromagnetic superexchange interaction between two $Co^{2+}$ ions is responsible for a new set of energy levels. The Raman data taken at low temperature on the sample corresponding to the composition x = 0.016 demonstrated the presence of two structures at about 6 $cm^{-1}$ and 13 $cm^{-1}$. These structures may be interpreted as electronic transitions between the ground state and the first excited state of a single $Co^{2+}$ ion in the substitution site of ZnO lattice and as a similar transition for $Co^{2+}$ ion pair, respectively.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 103-106
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manifestation of Spin-Glass-Like Behavior in the Organometallic Magnet
Autorzy:
Dyakonov, V. P.
Arciszewska, M.
Dobrowolski, W.
Szewczyk, A.
Szymczak, H.
Aksymentieva, E.
Varyukhin, V.
Zubov, E.
Gutowska, M. U.
Powiązania:
https://bibliotekanauki.pl/articles/2013705.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.40.Cx
Opis:
Ac susceptibility (χ$\text{}_{ac}$) and dc magnetization (M$\text{}_{dc}$) of the organometallic magnet Na[FeO$\text{}_{6}$(C$\text{}_{10}$H$\text{}_{8}$N)$\text{}_{3}$] have been studied in temperature range of 4.2-200 K, in an external magnetic field up to 16 kOe. Some peculiarities of the χ$\text{}_{ac}$ and M $\text{}_{dc}$ behavior, which are characteristic of spin-glasses, e.g. cusps in the susceptibility and zero-field-cooled magnetization, an irreversibility between the field-cooled and zero-field-cooled magnetization and dependences of the T$\text{}_{cusp}$ temperature on the frequency and the intensity of the magnetic field, were observed at low temperatures.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 863-866
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fermi Level Position in GaMnAs - a Thermoelectric Study
Autorzy:
Osinniy, V.
Jędrzejczak, A.
Arciszewska, M.
Dobrowolski, W.
Story, T.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2027483.pdf
Data publikacji:
2001-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Ck
75.30.Et
73.50.-h
Opis:
Thermoelectric power was studied in the temperature range 100≤ T≤300 K in 0.3-1μm thick ferromagnetic Ga$\text{}_{1-x}$Mn$\text{}_{x}$As epitaxial layers (0.015≤ x≤0.06) in order to determine Fermi energy E$\text{}_{F}$ and carrier concentration p. For 0.015≤ x≤0.05, at T=273 K we find E$\text{}_{F}$=275±50 meV and p=(2.5± 0.5)×10$\text{}^{20}$ cm$\text{}^{-3}$ (approximately Mn content independent). For x= 0.06, the Fermi energy decreases by about 100 meV with the corresponding reduction of hole concentration to p=1.2×10$\text{}^{20}$ cm$\text{}^{-3}$. At T=120 K, these parameters vary between E$\text{}_{F}$=380 meV and p=3.5×10$\text{}^{20}$ cm$\text{}^{-3}$ for x=0.015 to E$\text{}_{F}$=110 meV and p=5×10$\text{}^{19}$ cm$\text{}^{-3}$ for x=0.06.
Źródło:
Acta Physica Polonica A; 2001, 100, 3; 327-334
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in Eus-pbs Multilayers
Autorzy:
Story, T.
Swüste, C. H. W.
Swagten, H. J. M.
de Jonge, W. J. M.
Stachow-Wójcik, A.
Twardowski, A.
Arciszewska, M.
Dobrowolski, W.
Gałązka, R. R.
Sipatov, A. Yu.
Powiązania:
https://bibliotekanauki.pl/articles/2013042.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.70.Ak
Opis:
We present the results of ferromagnetic resonance studies of the thickness dependence of magnetic anisotropy in 2 series of EuS-PbS multilayers grown on (111) BaF$\text{}_{2}$ and (100) KCl substrates with the EuS thickness varying in the range d=6-70 Å. The anisotropy constant K was found to follow the dependence K(d)=K$\text{}_{V}$+2K$\text{}_{S}$/d , with the surface term K$\text{}_{S}$ larger for layers grown on BaF$\text{}_{2}$ as compared to KCl. This difference is discussed in terms of different thermal stress-induced distortions of cubic crystal lattice of EuS. We found that the thickness of EuS layer required for the perpendicular (to the layer) magnetization is d ≤ 2-3 Å, i.e., it is below 1 monolayer.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 435-438
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hight-Field Submillimeter Magneto-Spectroscopy on Hg(Fe)Se
Autorzy:
Portugall, O.
Von Ortenberg, M.
Yokoi, H.
Takeyama, S.
Miura, N.
Van Bockstal, L.
Herlach, F.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1886979.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Fs
Opis:
Magnetooptical phenomena in the zero-gap semimagnetic semiconductor Hg(Fe)Se are studied by various techniques in pulsed magnetic fields up to 150 T. Microscopical parameters are estimated in combination with results obtained from transport and magnetization measurements.
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 363-367
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and Magnetic Study of Gd Ions in Pb$\text{}_{1-y}$Sn$\text{}_{y}$Te
Autorzy:
Story, T.
Arciszewska, M.
Łazarczyk, P.
Łusakowski, A.
Górska, M.
Dobrowolski, W.
Witkowska, B.
Grodzicka, E.
Gałązka, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/1968424.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Ck
75.30.Et
Opis:
Electric conductivity, Hall effect and magnetic susceptibility of Pb$\text{}_{1-x-y}$ Sn$\text{}_{y}$Gd$\text{}_{x}$Te mixed crystals with 0.13 ≤ y ≤ 0.93 and 0.001 ≤ x ≤ 0.04 were experimentally studied over the temperature range 4K ≤ T ≤ 300 K. The incorporation of Gd ions into the Pb$\text{}_{1-y}$Sn$\text{}_{y}$Te matrix results in semi-metallic n-type conductivity of the crystals with y < 0.6. For crystals with y > 0.6 one observes only semi-metallic p-type conductivity. We present a model explaining these results in terms of the Sn composition dependence of the location of Gd$\text{}^{2+}\text{}^{/}\text{}^{3+}$ level with respect to the band edges of PbSnGdTe.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 997-1000
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of "As-Prepared" and Chemically Modified Multiwalled Carbon Nanotubes
Autorzy:
Kuryliszyn-Kudelska, I.
Małolepszy, A.
Mazurkiewicz, M.
Stobinski, L.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/2047920.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.De
81.20.Ym
75.75.-c
Opis:
In this work we have studied the structural and magnetic properties of "as-prepared" multiwalled carbon nanotubes, synthesized by the chemical vapor deposition method, and chemically modified multiwalled carbon nanotubes. Transmission electron microscopy was used to show multiwalled carbon nanotubes structure. The results of systematic magnetic property measurements on multiwalled carbon nanotubes are presented. The static and dynamic magnetic responses, such as the temperature dependence of the linear AC susceptibility and DC magnetization up to 9 T were studied. We have observed significant changes in magnetic AC susceptibility and magnetization for "as-prepared" and chemically modified multiwalled carbon nanotubes samples.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 597-599
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Scattering from ZnO(Fe) Nanoparticles
Autorzy:
Romčević, N.
Kostić, R.
Romčević, M.
Hadžić, B.
Kuryliszyn-Kudelska, I.
Dobrowolski, W.
Narkiewicz, U.
Sibera, D.
Powiązania:
https://bibliotekanauki.pl/articles/1811980.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.-e
78.30.Fs
78.67.-n
Opis:
Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine composition of the samples (ZnO, Fe₂O₃, ZnFe₂O₄) and the mean crystalline size (8-52 nm). In this paper we report the experimental spectra of the Raman scattering (from 200 to $1600 cm^{-1}$). Main characteristics of experimental Raman spectrum in 200 to $1600 cm^{-1}$ spectral region are: sharp peak at $436 cm^{-1}$ and broad two-phonon structure at ≈ $1150 cm^{-1}, typical of ZnO;broad structure below $700 cm^{-1}$ that has different position and shape in case of ZnFe₂O₄ or Fe₂O₃ nanoparticles.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1323-1328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetotransport Study of MBE grown Pb$\text{}_{1-x}$Eu$\text{}_{x}$Se Epilayers
Autorzy:
Dobrowolski, W.
Grodzicka, E.
Story, T.
Lambrecht, A.
Bottner, H.
Tacke, M.
Powiązania:
https://bibliotekanauki.pl/articles/1950743.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Le
73.50.Jt
Opis:
Hall effect and electron conductivity investigations of MBE grown epilayers of Pb$\text{}_{1-x}$Eu$\text{}_{x}$Se (0 ≤ x ≤ 0.06) as a function of temperature and magnetic field are reported. The strong Hall coefficient dependence on the magnetic field was found for p-type samples grown with Se excess. The possible origins of this effect are discussed.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 759-762
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Sn$\text{}_{1-x}$Gd$\text{}_{x}$Te (0.002 ≤ x ≤ 0.09)
Autorzy:
Story, T.
Arciszewska, M.
Dobrowolski, W.
Gołacki, Z.
Górska, M.
Grodzicka, E.
Łusakowski, A.
Dynowska, E.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1952098.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Ck
75.30.Et
Opis:
Magnetic, transport and structural properties of bulk crystals of Sn$\text{}_{1-x}$Gd$\text{}_{x}$Te with Gd content 0.002 < x < 0.09 and varying carrier concentrations obtained by an isothermal annealing were studied in the temperature range T = 1.5 - 80 K. We found the effect of resonant increase in antiferromagnetic spin-spin exchange interactions in the crystals with 0.025 ≤ x ≤ 0.05. No effect was found in crystals either with higher (x > 0.05) or with lower (x < 0.025) Gd concentration. The observed Gd composition dependence of the magnetic and transport properties of SnGdTe can be explained in a proposed model relating these experimental properties to the Gd composition induced shift of the position of Gd$\text{}^{3+}\text{}^{/}\text{}^{2+}$ level with respect to the top of the valence band of SnGdTe.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 935-938
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(Eu,Gd)Te - MBE Growth and Characterization
Autorzy:
Dziawa, P.
Taliashvili, B.
Domuchowski, W.
Łusakowska, E.
Arciszewska, M.
Demchenko, I.
Dobrowolski, W.
Dybko, K.
Fedorych, O. M.
Nadolny, A. J.
Osinniy, V.
Petrouchyk, A.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038228.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.15.Hi
Opis:
Monocrystalline thin layers of (Eu,Gd)Te, n-type ferromagnetic semiconductor, were grown by molecular beam epitaxy technique on BaF$\text{}_{2}$ (111) substrates. Reflection high-energy electron diffraction, X-ray diffraction, and atomic force microscopy characterization proved epitaxial mode of growth and high crystal quality of the layers. Magnetic susceptibility and magnetic resonance measurements showed that in (Eu,Gd)Te layers ferromagnetic transition takes place at about 13 K. Electrical characterization carried out by the Hall effect and resistivity measurements revealed very high electron concentration of 10$\text{}^{20}$~cm$\text{}^{-3}$ and sharp maximum of resistivity at transition temperature.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 215-221
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant State of 4f$\text{}^{14}\text{}^{/}\text{}^{13}$ Yb Ion in Pb$\text{}_{1-x}$Ge$\text{}_{x}$Te
Autorzy:
Grodzicka, E.
Dobrowolski, W.
Story, T.
Slynko, E. T.
Vygranenko, Yu.K.
Willekens, M. M. H.
Swagten, H. J. M.
de Jonge, W. J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1950801.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Ht
75.20.Ck
Opis:
The study of transport and of magnetic properties of Pb$\text{}_{1-x}$Ge$\text{}_{x}$Te:Yb mixed crystals (0 ≤ x ≤ 0.04) is reported. It is shown that Yb forms a donor state resonant with the PbTe valence band. The donor state position may be tuned (shifted relative to the energy gap) by admixture of Ge. The properties of the Yb ion in the Pb$\text{}_{1-x}$Ge$\text{}_{x}$Te matrix makes the system unique from the point of view of magnetic properties. It is demonstrated that the change of the conductivity type from p to n induces transitions from the paramagnetic state to the diamagnetic one.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 801-804
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Frequency Raman Scattering from ZnO(Fe) Nanoparticles
Autorzy:
Kostić, R.
Romčević, N.
Romčević, M.
Hadžić, B.
Rudolf, R.
Kuryliszyn-Kudelska, I.
Dobrowolski, W.
Narkiewicz, U.
Sibera, D.
Powiązania:
https://bibliotekanauki.pl/articles/1807817.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Fs
78.67.-n
Opis:
Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine the sample composition and the mean crystalline size. Low-frequency Raman modes were measured and assigned according to confined acoustic vibrations of spherical nanoparticles. Frequencies of these vibrational modes were analyzed in elastic continuum aproximation, which considers nanoparticle as homogeneous elastic sphere.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 65-67
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Magnetic Properties of PbTe(Ni)
Autorzy:
Romčević, N.
Trajić, J.
Romčević, M.
Stojanović, D.
Kuznetsova, T.
Khokhlov, D.
Dobrowolski, W.
Rudolf, R.
Anžel, I.
Powiązania:
https://bibliotekanauki.pl/articles/1808059.pdf
Data publikacji:
2009-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.-e
63.20.Kr
78.30.-j
Opis:
Far-infrared and magnetic properties of Ni doped PbTe ($Z_Ni$ = 1× $10^{19}$ at./$cm^{3}$) single crystal are investigated in a broad range of temperature and magnetic fields. Far-infrared reflection spectra were analyzed using a fitting procedure based on the modified plasmon-two phonon interaction model. Together with the strong plasmon-two longitudinal optical phonon coupling we obtained a local mode of Ni at about 180 $cm^{-1}$. This mode intensity depends on temperature. Magnetic measurements shows that PbTe alloys doped with Ni reveals weak ferromagnetic interaction between magnetic ions.
Źródło:
Acta Physica Polonica A; 2009, 115, 4; 805-807
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Order and Magnetic Inhomogeneities in SnCrTe-PbCrTe Solid Solutions
Autorzy:
Kilanski, L.
Szymański, M.
Brodowska, B.
Górska, M.
Szymczak, R.
Podgórni, A.
Avdonin, A.
Reszka, A.
Kowalski, B.
Domukhovski, V.
Arciszewska, M.
Dobrowolski, W.
Slynko, V.
Slynko, E.
Powiązania:
https://bibliotekanauki.pl/articles/1376790.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ga
75.30.Hx
75.30.Et
75.50.Pp
Opis:
We present the studies of structural, electrical and magnetic properties of bulk $Sn_{1-x-y}Pb_xCr_yTe$ mixed crystals with chemical composition 0.18 ≤ x ≤ 0.35 and 0.007 ≤ y ≤ 0.071. The magnetometric studies indicate that for the high Cr-content, y=0.071, the alloy shows ferromagnetic alignment with the Curie temperature, $T_{C}$, around 265 K. The $Cr_5Te_8$ clusters are responsible for the ferromagnetic order. At low Cr content, y ≈ 0.01, a peak in the ac magnetic susceptibility identified as the cluster-glass-like transition is observed at a temperature about 130 K. The cluster-glass-like transition is likely due to the presence of $Cr_2Te_3$ clusters in the samples with y ≈ 0.01. The transport characterization of the samples indicated strong metallic p-type conductivity with relatively high carrier concentration, n > $10^{20}$ $cm^{-3}$, and carrier mobility, μ > 150 $cm^2$/(V s).
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1203-1206
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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