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Wyszukujesz frazę "75.50.+g" wg kryterium: Temat


Tytuł:
SWR Studies of Higher-Order Surface Anisotropy Terms in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Diep, H.
Powiązania:
https://bibliotekanauki.pl/articles/1030424.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
76.60.-k
Opis:
We extend the theory of spin-wave resonance (SWR) by introducing a new formula representing the surface pinning parameter as a series of contributions from different anisotropies existing in (Ga,Mn)As thin films. Comparing our theory with the reported experimental studies of SWR in thin films of the ferromagnetic semiconductor (Ga,Mn)As, we find that besides the first-order cubic anisotropy, higher-order cubic anisotropies (in the second and third orders) as well as uniaxial anisotropies (perpendicular in the first and second orders, and in-plane diagonal) occur on the surface of this material. To our best knowledge this is the first report of the existence of higher-order surface anisotropy fields in (Ga,Mn)As thin films.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 635-638
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Frequency Absorbing Performances of Carbonyl Iron/MnZn Ferrite/PVC Polymer Composites
Autorzy:
Dosoudil, R.
Ušáková, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032831.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Bb
76.50.+g
75.78.-n
72.80.Tm
78.20.Ci
41.20.Jb
Opis:
We have prepared composite materials with a mixture of carbonyl iron (CI) and manganese-zinc ferrite (MnZn) as filler and polyvinylchloride (PVC) as polymer matrix, and then electromagnetic wave absorption properties of CI/MnZn/PVC composites have been studied in the frequency range from 10 MHz to 6.5 GHz. Increasing carbonyl iron loading (to the detriment of MnZn ferrite) results in the rise of permeability and magnetic resonance loss (especially in GHz frequency range) which leads to the shift of absorption peak towards lower frequency and to the decrease of matching thickness. On the contrary, increasing MnZn ferrite loading (to the detriment of carbonyl iron) results in higher absorption bandwidth. The obtained results indicate that the prepared flexible composites may be useful as thin and/or wideband microwave absorbers.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 687-689
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and structural studies of GeMnSnTe epitaxial layers
Autorzy:
Grochot, A.
Knoff, W.
Taliashvili, B.
Wołkanowicz, W.
Minikayev, R.
Pieniążek, A.
Łusakowska, E.
Sawicki, M.
Jantsch, W.
Story, T.
Przybylińska, H.
Powiązania:
https://bibliotekanauki.pl/articles/1055147.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Pp
76.50.+g
Opis:
MBE grown Ge_{1-x-y}Mn_xSn_yTe layers with Mn content ranging from 10 to 30% and Sn content ranging from 2 to 5% have been characterized with X-ray diffraction, energy-dispersive X-Ray spectroscopy, atomic force microscopy, SQUID magnetometry, and ferromagnetic resonance. All layers (except the one with the highest Mn and Sn content) were found to be single phase rhombohedral, with the distortion axis perpendicular to the layer surface, and ferromagnetic. Ferromagnetic resonance studies have shown that co-doping with a few percent of tin makes the lattice more rigid and changes considerably the magnetocrystalline anisotropy, from purely uniaxial in GeMnTe to distorted cubic in Ge_{1-x-y}Mn_xSn_yTe at the same Mn content.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 340-342
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Synthetic Gehlenite Glass Microspheres
Autorzy:
Majerová, M.
Dvurečenskij, A.
Cigáň, A.
Škrátek, M.
Prnová, A.
Kraxner, J.
Galusek, D.
Maňka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032688.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Kf
75.50.Kj
91.60.Pn
75.20.-g
75.50.Lk
Opis:
In the paper, gehlenite amorphous microspheres were prepared by the flame synthesis of a powder precursor. In the first step, the precursor was prepared from a stoichiometric mixture of CaCO₃, Al₂O₃ and SiO₂ by a standard solid-state reaction method. Next, the precursor was sprayed into a CH₄-O₂ flame with the temperature of around 2200°C and molten droplets of synthetic gehlenite were rapidly cooled by distilled water. Structural and detailed magnetic properties were studied by the optical microscopy, X-ray diffraction and QD SQUID magnetometer. The gehlenite microspheres show a complex magnetic behaviour that is a function of the temperature and the magnetic field, e.g. diamagnetism and paramagnetism at 300 K and 2 K, respectively.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 699-701
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Study of Nanocrystalline TiB₂, TiC, B₄C Powders Doped to AISI 316L Austenitic Steel
Autorzy:
Bodziony, T.
Kaczmarek, S.
Biedunkiewicz, A.
Leniec, G.
Figiel, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032403.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.55.Jg
75.20.-g
75.50.-y
75.50.Bb
76.30.-v
Opis:
The investigations into ferromagnetic resonance and magnetic susceptibility of nanocrystalline TiB₂, TiC, and B₄C powders (Ti-B-C system) doped to AISI 316L austenitic steel with different amounts (3 vol.%, 5 vol.% and 7 vol.%) have been carried out. The ferromagnetic resonance spectra were recorded in the temperature range from helium up to room temperature. The three tested composite samples contain a number of magnetic phases in different proportions. They reveal a structure originating from several different complex magnetic centers. The composites revealed such magnetic phenomena as paramagnetism, (anti)ferromagnetism, and superparamagnetism. Magnetic susceptibility investigations supported the ferromagnetic resonance studies and their analysis. Magnetic properties of the TiB₂, TiC, B₄C powders doped to AISI steel may play important role in further possible applications of these composite systems.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 62-68
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructural and magnetic characteristics of divalent Zn, Cu and Co-doped Ni ferrites
Autorzy:
Šoka, M.
Dosoudil, R.
Ušáková, M.
Powiązania:
https://bibliotekanauki.pl/articles/1054856.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
76.50.+g
75.78.-n
74.62.Bf
Opis:
Divalent zinc, copper and cobalt doped nickel ferrites with the chemical formula Ni_{1-x-y-z}Zn_{x}Cu_{y}Co_{z}Fe₂O₄ where x values ranging from 0.4 to 0.6, y=0.1, z=0.01 and 0.02 have been synthesized by conventional ceramic method. The effect of Zn²⁺, Cu²⁺ and Co²⁺ ions substitution on the selected microstructural and magnetic characteristics have been investigated to examine the utility of prepared ferrite materials for high-frequency applications. X-ray diffraction measurements confirmed the single-phase spinel cubic structure in all the samples and modifications in lattice parameter according to the ionic radii size of doped ions. The net magnetic moment, given by the differences between the magnetic moments of A and B sublattice, increased with raising substitution of Ni²⁺ ions. The measured frequency dispersion of complex permeability was discussed in terms of the changes in chemical composition, microstructure and the associated processes of resonance and/or relaxation due to domain wall movements and damping of spin rotations contributing to the fall of permeability and rise of magnetic losses.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 690-692
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Existence Conditions of Surface Spin Wave Modes in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/1398676.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
Opis:
Spin-wave resonance is a newly emerged method for studying surface magnetic anisotropy and surface spin-wave modes in (Ga,Mn)As thin films. The existence of surface spin-wave modes in (Ga,Mn)As thin films has recently been reported in the literature; surface spin-wave modes have been observed in the in-plane configuration (with variable azimuth angle $\phi_M$ between the in-plane magnetization of the film and the surface [100] crystal axis), in the azimuth angle range between two in-plane critical angles $\phi_{c1}$ and $\phi_{c2}$. We show here that cubic surface anisotropy is an essential factor determining the existence conditions of the above-mentioned surface spin-wave modes: conditions favorable for the occurrence of surface spin-wave modes in a (Ga,Mn)As thin film in the in-plane configuration are fulfilled for those azimuth orientations of the magnetization of the sample that lie around the hard axes of cubic magnetic anisotropy. This implies that a hard cubic anisotropy axis can be regarded in (Ga,Mn)As thin films as an easy axis for surface spin pinning.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 117-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Temperature Properties of Inhomogeneous Magnetic Multilayers
Autorzy:
Urbaniak-Kucharczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1387020.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.70.Ak
76.50.+g
Opis:
System of two magnetic layers with nonuniform distribution of anisotropy parameter and exchange coupled by nonmagnetic spacer is studied by means of the Green function approach. Our attention is focussed on the elementary excitations and low temperature magnetisation behavior. The spin wave parameter B in the Bloch law $T^{3/2}$ is found as an oscillatory function of a spacer thickness. The effects of damping leading to non-zero line-width of ferromagnetic resonance peaks are also taken into account. As a result the dependence of resonance line-width on parameters characterizing system under consideration is obtained for the case of uniform anisotropy parameter and for quadratic distribution of this parameter in magnetic layers, respectively.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 543-545
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in (Ge,Mn)Te Layers
Autorzy:
Knoff, W.
Łusakowski, A.
Wołoś, A.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/1386196.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
76.50.+g
Opis:
Ferromagnetic resonance study of magnetic anisotropy is presented for thin layers of IV-VI diluted magnetic semiconductor (Ge,Mn)Te with Mn content of 12 and 21 at.% grown by molecular beam epitaxy on BaF₂ (111) substrates. The layers with low Mn content grow in the rhombohedral crystal structure and exhibit perpendicular magnetic anisotropy whereas the layers with Mn content higher than about 20 at.% are of cubic (rock-salt) structure and show regular easy-plane type magnetic anisotropy. The quantitative analysis of the angular dependence of the ferromagnetic resonant field is performed taking into account the magnetic energy contributions due to rhombohedral distortion (axial term along the (111) growth direction of the layer) and the crystal field terms allowed for ferromagnetic systems of rhombohedral symmetry.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 404-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Centres in Functionalized Graphene
Autorzy:
Majchrzycki, Ł.
Augustyniak-Jabłokow, M.
Strzelczyk, R.
Maćkowiak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1387002.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Ak
81.05.ue
76.50.+g
Opis:
Discussion of the origin of paramagnetic centres observed by electron paramagnetic resonance in graphene oxide (GO) and reduced graphene oxide (rGO) is done on the assumption that GO can be considered as a functionalized graphene. This leads to the conclusion that the narrow signal with g close to 2, observed for GO and thermally reduced GO, is due to paramagnetic centres localized on defects and exchange coupled to conduction electrons. Randomness of graphene modification results in variety of parameters of EPR signals. The broad signals observed in GO and rGO and ascribed to magnetic clusters on the zig-zag edge states indicate that the edge magnetism can be preserved by functionalization.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 540-542
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manipulation of Exchange Coupling in Py/Co/Cr Multilayer Thin Films
Autorzy:
Aköz, M.
Parlak, U.
Şahin, Y.
Tavşan, D.
Tarcan, E.
Öztürk, O.
Tokdemir Öztürk, S.
Erkovan, M.
Powiązania:
https://bibliotekanauki.pl/articles/1401229.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.50.Cc
76.50.+g
Opis:
The main issue addressed in present study is exchange coupling modification between ferromagnetic layers through non-magnetic spacer layers using extra ultra-thin ferromagnetic layers (Co). In order to achieve this goal, we prepared Cr(50 Å) / Py(20 Å) / Co(5 Å) / Cr(7, 10, 13 Å) / Co(5 Å) / Py (30 Å) / Cr(50Å) / Si using magnetron sputtering at UHV conditions and characterized by Ferromagnetic Resonance (FMR) technique. As the present study results were compared to our previous study on (Py/Cr), the exchange coupling energy was increased ten times with the cobalt thin layer
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 992-994
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model for the Surface Anisotropy Field Observed in Spin-Wave Resonance in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/1386858.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
Opis:
In this study we show why spin-wave resonance in a (Ga,Mn)As thin film may, in different conditions, meet the assumptions of either the surface inhomogeneity (SI) or the volume inhomogeneity (VI) model.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 508-510
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Results on the Density of Electronic States, Superexchange Interaction, and Electrical Conduction in Transition-Metal Salts
Autorzy:
Grado-Caffaro, M.
Powiązania:
https://bibliotekanauki.pl/articles/1401901.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.-g
75.20.En
75.50.-y
75.76.+j
Opis:
We investigate several issues related to the electronic states in the ligand orbital of a given transition-metal salt as, for example, a K₂CuCl₄·2H₂O-type compound. In fact, to get our calculation, we start from an expression for the electronic density of states in a compound of the above type. In addition, various aspects related to superexchange interaction in both the paramagnetic and ferromagnetic cases are discussed and the electronic conduction process in the ligand orbital is studied.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 394-397
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Ferromagnetic Resonance in Micron and Sub-Micron Amorphous Wires
Autorzy:
Kraus, L.
Ababei, G.
Powiązania:
https://bibliotekanauki.pl/articles/1385662.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Ds
75.50.Kj
76.50.+g
Opis:
Ferromagnetic resonance in glass-coated amorphous microwires FeSiB and CoFeSiB with the diameters varying from 133 nm to 25 μm and the glass thickness about 10 μm was measured at frequency of 9.5 GHz. Electric polarization of the wire can substantially amplify the microwave magnetic field on the sample surface. This allows us to achieve the threshold fields for nonlinear behavior with microwave power of only few mW. Above some critical value of incident power a distortion of central part of FMR curves is observed for FeSiB wires. For diameters less than 6 μm a series of sharp, nearly equidistant peaks appears with the period δH inversely proportional to the wire diameter. The phenomenon is explained by the parametric excitation of dipole-exchange modes via the first order Suhl spin-wave instability and the spin-wave confinement in very thin wires. In the CoFeSiB wires the nonlinear phenomena cannot be achieved even with the maximum power available (about 25 mW). It is probably because the threshold field is higher due to larger Gilbert damping constant and lower saturation magnetization of this alloy.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 359-361
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasi-Two-Dimensional Ferromagnetism in Cr₂Te₃ and Cr₅Te₈ Crystals
Autorzy:
Bester, M.
Stefaniuk, I.
Kuzma, M.
Powiązania:
https://bibliotekanauki.pl/articles/1386445.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.50.Cc
Opis:
The crystal structure of CrTe suggests two-dimensional magnetism in the plane perpendicular to the c axis. It is consistent with the temperature dependence of the g factor and EPR lines width observed. In the present paper we investigate the CrTe alloy which has been prepared by melting of the powdered Cr₂Te₃ in evacuated quartz ampoule at the temperature 1600 K. ESR spectra were recorded using X-band (9.4 GHz) spectrometer provided with gas nitrogen cryostat. The shape of the EPR line depends strongly on the temperature. In the vicinity of the room temperature the lines become very wide and weak or disappear completely. At lower temperatures the shape of the lines approaches the Dyson function. The asymmetry of lines is attributed to the strong exchange interactions as well as to the semimetal electrical conductivity. Above the room temperature the shape of spectra is characteristic for the paramagnetic phase. Results were addressed based on the model of critical spin fluctuations in two-dimensional Heisenberg magnet proposed by Eremin et al.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 433-435
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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