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


Tytuł:
X-Ray Magnetic Scattering
Autorzy:
Cooper, M.
Powiązania:
https://bibliotekanauki.pl/articles/1920839.pdf
Data publikacji:
1992-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.Dp
75.50.-y
78.70.-g
78.70.Ck
Opis:
Magnetic X-ray diffraction with synchrotron radiation is now an established technique for studies of antiferromagnets. The problems associated with the small magnetic scattering cross-section being alleviated by the dramatic enhancements found near absorption edges through resonant exchange scattering. The technique is particularly useful for those materials that require high wavevector resolution to reveal the structural phase transitions that accompany the magnetic ordering process or those that are difficult to investigate with neutrons, (e.g. samarium, for which recent results are presented). In the actinides the work is also motivated by the objective of performing an empirical separation of the spin and orbital components of magnetisation. Diffraction studies of ferromagnets require circular polarised radiation and suffer from the superposition of the small magnetic signal and the charge scattering; to date Laue methods have proved more successful than monochromatic beam studies. Ferro- and ferrimagnets can also be studied by Compton (inelastic) scattering but the cross-section is less well established: considerable effort has been directed to determining whether orbital magnetisation can be measured in these experiments and results on HoFe$\text{}_{2}$ now indicate this is not so. Magnetic Compton profiles provide information about the momentum distribution of electrons with unpaired spins, and this, together with magnetisation data can provide the basis for the separation of spin and orbital magnetisation.
Źródło:
Acta Physica Polonica A; 1992, 82, 1; 137-146
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrafast Coherent Control of Spin Precession Motion by Terahertz Magnetic Pulses
Autorzy:
Nakajima, M.
Yamaguchi, K.
Suemoto, T.
Powiązania:
https://bibliotekanauki.pl/articles/1489996.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.78.Jp
42.50.Md
76.50.+g
78.20.Ls
Opis:
We demonstrated coherent control of spin precession motion due to the ferromagnetic resonance induced by magnetic field component of ultrashort terahertz pulses. The amplitude of the precession can be controlled by the pulse separation time of the double pulse excitation technique. We succeeded in observing the energy transfer between spin and photon systems, and the energy of the spin system is returned to the second terahertz pulses instantaneously when the precession amplitude is cancelled.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 343-346
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theory of Nonlinear Ferromagnetic Resonance in the Samples with Magnetostatic and Exchange Boundary Conditions Imposed
Autorzy:
Krawiecki, A.
Sukiennicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1929206.pdf
Data publikacji:
1993-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.30.Ds
75.70.-i
Opis:
General theory of nonlinear ferromagnetic resonance is presented for samples with the usual magnetostatic and exchange boundary conditions imposed at the sample surface. In such samples the Suhl instabilities and other nonlinear effects occur due to nonlinear interactions of magnetostatic or dipole-exchange modes. All relevant types of interactions are included in the Hamiltonian: with the pumping field, three- and four-mode ones. Analytic calculation of the Suhl thresholds in the three possible types of instabilities in perpendicular and parallel pumping is performed for the sample in the shape of a thin slab.
Źródło:
Acta Physica Polonica A; 1993, 83, 4; 505-515
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Phase Decomposition on Magnetic Structure of $Cu_{0.4}Mn_{0.3}Ni_{0.3}$ Alloy
Autorzy:
Świderska, K.
Jankowska-Kisielińska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1385743.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
64.75.-g
75.40.-s
75.47.Np
75.50.Ee
81.40.Rs
Opis:
The purpose of present investigation was to study the effects of phase decomposition of the $Cu_{0.4}Mn_{0.3}Ni_{0.3}$ alloy on its magnetic ordering. The single-crystal sample was examined by elastic neutron scattering before and after five subsequent annealing runs. The results indicate that in small fraction of the quenched sample volume there are two types of antiferromagnetic order: one of them AF1 of the long range, the other one of the short range. Ageing induces phase decomposition which yields disappearance of AF1 long range order and increase of the volume of new ordered phase. The results of the investigations of the aged sample indicate that regions of new tetragonal phase exhibit antiferromagnetic ordering with magnetic moments of Mn atoms arranged as in the pure compound MnNi but with unequal domain distribution. The intensity of magnetic component of super-structure reflections increases with the duration of ageing at lower rate than component due to atomic order.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 394-396
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of Magnetization Damping in Heusler Alloy Films
Autorzy:
Dubowik, J.
Załęski, M.
Głowiński, H.
Gościańska, I.
Powiązania:
https://bibliotekanauki.pl/articles/1534143.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.70.Ak
75.78.Jp
Opis:
The Gilbert damping for $Co_2CrAl (Co_2Cr_{0.3}Fe_{0.7}Al)$ and $Ni_2MnSn$ Heusler alloy films was investigated as a function of temperature. The best films reveals the Gilbert damping nearly independent of temperature. Magnetic relaxation in $Co_2CrAl$ is strongly influenced by magnetic inhomogeneities due to phase separation. The best $Ni_2MnSn$ epitaxial films have comparable Gilbert damping α of 6× $10^{-3}$ as half-metallic $Co_2Cr_{0.3}Fe_{0.7}Al$ films with α = 3 × $10^{-3}$.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 848-850
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of Exchange Anisotropy of FeNi/FeMn Bilayers
Autorzy:
Żuberek, R.
Gutowski, M.
Szymczak, H.
Gnatchenko, S.
Merenkov, D.
Bludov, A.
Verkin, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813596.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.Ac
75.30.Et
75.70.-i
76.50.+g
Opis:
The influence of the bilinear and biquadratic coupling on the exchange anisotropy of the ferromagnetic/antiferromagnetic bilayer was studied by variable angle and temperature dependent ferromagnetic resonance. From the angular dependence of the resonance field the bilinear and biquadratic exchange coupling constants were determined.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 167-170
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synchronization Among Spin-Wave Amplitudes in Chaotic Nonlinear Ferromagnetic Resonance
Autorzy:
Krawiecki, A.
Powiązania:
https://bibliotekanauki.pl/articles/2013977.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.30.Ds
05.45.+b
Opis:
A model of chaos in high-power ferromagnetic resonance in coincidence regime, based on three-magnon interactions of the uniform mode with a group of pairs of parametric spin waves, is investigated numerically. The results are interpreted from the point of view of chaotic synchronization theory. If all spin waves are identical, all of them are excited above the first-order Suhl instability threshold and in the chaotic regime their amplitudes show marginal synchronization, i.e. they differ only by a multiplicative factor, constant in time. If spin waves have slightly different instability thresholds, only one or few of them are excited. In the latter case, addition of weak thermal noise changes the results qualitatively. For low rf field amplitude, but above the threshold for chaos, still only few spin-wave pairs are excited above the thermal level. For higher rf field amplitude all spin waves in the group are excited, and their amplitudes are not synchronized. These results suggest that low correlation dimension of chaotic attractors, observed often in nonlinear ferromagnetic resonance, can be connected with chaotic synchronization among spin-wave amplitudes, in particular just above the threshold for chaos.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 947-950
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Surface Magnetic Anisotropy of Epitaxial La$\text{}_{0.7}$Mn$\text{}_{1.3}$O$\text{}_{2.84}$ Thin Films
Autorzy:
Aleshkevych, P.
Baran, M.
Dyakonov, V.
Szymczak, R.
Szymczak, H.
Baberschke, K.
Lindner, J.
Lenz, K.
Powiązania:
https://bibliotekanauki.pl/articles/2046886.pdf
Data publikacji:
2006-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.70.-i
Opis:
A spin-wave resonance technique was used to collect information on elementary magnon excitations in high quality epitaxial La$\text{}_{0.7}$Mn$\text{}_{1.3}$O$\text{}_{2.84}$ films prepared by dc-magnetron sputtering. It was found that besides bulk spin-wave modes, the spin-wave resonance spectrum includes also the surface spin waves. The value of spin-wave stiffness constant D=156 meV·Å$\text{}^{2}$ was found. The values of the surface magnetic anisotropy on both surfaces and their angular dependence were determined. The experimentally found spin-wave resonance spectra were explained based on the surface-inhomogeneity model. The effect of surface anisotropy on the spin-wave excitation conditions in epitaxial La$\text{}_{0.7}$Mn$\text{}_{1.3}$O$\text{}_{2.84}$ films was investigated. Spin-wave resonance data give an indirect evidence of periodic charge-ordered stripes formation.
Źródło:
Acta Physica Polonica A; 2006, 110, 1; 57-70
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Stochastic Multiresonance in Hierarchical Networks
Autorzy:
Krawiecki, A.
Kaim, M.
Powiązania:
https://bibliotekanauki.pl/articles/1409029.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.-a
75.30.Ds
76.50.+g
Opis:
Systems with a structure of hierarchical networks, consisting of simple units placed in the nodes and interacting along the edges of the network, are ubiquitous in the modern society and economy. In this paper the problem of signal detection and transmission in such systems in the presence of noise is analyzed from the point of view of stochastic resonance. As examples simple tree-like and more complex Ravasz-Barabási networks of interacting threshold elements are considered. It is shown that stochastic multiresonance is often observed, a phenomenon characterized by the presence of two or more maxima of the output signal-to-noise ratio as a function of the input noise intensity. The origin of the additional maxima, which occur for small noise intensities, can be related to the structure of the interactions, thus the observed phenomenon is an example of structural stochastic multiresonance.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-72-B-76
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SrLaGaO$\text{}_{4}$-SrLaAlO$\text{}_{4}$ Solid Solutions - Substrate Materials with Tuneable Lattice Parameter for Various HTSC Compounds
Autorzy:
Berkowski, M.
Fink-Finowicki, J.
Mojaiskaia, E.
Powiązania:
https://bibliotekanauki.pl/articles/1964363.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.-d
81.10.Fq
61.50.Νw
64.75.+g
Opis:
The increase in Τ$\text{}_{c}$ for high temperature superconductors can be realized, among others, by appropriate substrate/film combinations. SrLaGaO$\text{}_{4}$-SrLaΑlO$\text{}_{4}$ solid solutions were grown by the Czochralski method. The already achieved results allow to obtain single crystals of SrLaΑl$\text{}_{1-x}$Ga$\text{}_{x}$O$\text{}_{4}$ with lattice constant a in the range from 0.3754 to 0.3775 nm, and SrLaGa$\text{}_{1-x}$Αl$\text{}_{x}$O$\text{}_{4}$ crystals with lattice constant a in the range from 0.3843 to 0.3826 nm. Electron-probe microanalysis along obtained single crystals was used for determination of segregation coefficient between aluminum and gallium ions.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 182-186
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of Noise-Free Stochastic Resonance in Spin-Wave Chaos
Autorzy:
Krawiecki, A.
Reibold, E.
Benner, H.
Sukiennicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/2013991.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.30.Ds
05.45.+b
05.40.+j
Opis:
Numerical simulations of noise-free stochastic resonance and aperiodic stochastic resonance in chaotic ferromagnetic resonance are presented. The model, based on three-magnon interactions between the externally excited uniform mode and pairs of spin waves, shows on-off intermittency. The rf magnetic field amplitude is slowly modulated by a small periodic or aperiodic signal, and the output signal, which reflects the occurrence of laminar phases and bursts in the time series of spin-wave amplitudes, is analyzed. On variation of the dc magnetic field the signal-to-noise ratio of the output signal and the correlation function between modulation and output signal pass a maximum, which indicates the occurrence of periodic and aperiodic stochastic resonance, respectively. The role of thermal magnon excitations in the occurrence of this maximum is clarified. The results are compared with experimental findings obtained in other types of intermittency.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 975-978
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
Tytuł:
Phase Relations in Gd$\text{}_{2}$O$\text{}_{3}$-CeO$\text{}_{2}$-CuO System at 980°C. Part I
Autorzy:
Horyń, R.
Sikora, A.
Bukowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2041467.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
Phase equilibria in Gd$\text{}_{2}$O$\text{}_{3}$-CeO$\text{}_{2}$-CuO system were studied based on samples obtained from appropriate mixtures of the starting components, prepared by a conventional solid state reaction in air. The phase relations prevalent in this system have been deduced based on X-ray diffraction of well-equilibrated samples. An isothermal cross-section diagram through the system at 980°C is presented and chemical constitution of the Ce-doped Gd$\text{}_{2}$CuO$\text{}_{4}$ phase is proposed.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 727-731
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase and Structural Study of Self-Doped La$\text{}_{1-x-y}$Ca$\text{}_{x}$Ø$\text{}_{y}$MnO$\text{}_{3+δ}$
Autorzy:
Figueiras, F.
Araújo, J. P.
Amaral, V. S.
Tavares, P. B.
Lopes, A. B.
Vieira, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2037125.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
To understand the combined effect of divalent ion and A-site vacancy (Ø) self-doping, beyond the binary La$\text{}_{1-x}$MnO$\text{}_{3}$ system, polycrystalline La$\text{}_{1-x-y}$Ca$\text{}_{x}$Ø$\text{}_{y}$MnO$\text{}_{3+δ}$ samples were studied. Samples with Ca substitution and excess Mn in the range x<0.33 and y<0.45, respectively, were prepared by standard solid-state reactions. Structural and phase analysis of the samples were done by X-ray diffraction and transmission electron microscopy. The manganite structure in this composition range includes rhombic and orthorhombic phases. Most samples contain the hausmanite phase (Mn$\text{}_{3}$O$\text{}_{4}$) coexisting with the manganite phase. A small amount of perovskite related AMn$\text{}_{7}$O$\text{}_{12}$ (A=La,Ca) structure near the hausmanite-manganite boundary is also found in samples treated in oxygen atmosphere. The calculated vacancy content accommodated in the manganite phase can be higher than 1/8, the reported limit for La$\text{}_{1-x}$MnO$\text{}_{3}$, which is confirmed in our x=0 sample. For the compositions studied, a ferromagnetic metallic behavior below T$\text{}_{C}$ is found, confirming the stability of the Mn sublattice, and near the optimum stoichiometric ((x=0. 33, y=0) system, a net A-site vacancy content (up to y=0.2) does not degrade the magnetic and electric properties.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 173-182
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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