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Wyszukujesz frazę "75.70.Cn" wg kryterium: Wszystkie pola


Tytuł:
Novel Mechanism of Biquadratic Coupling in Magnetic Superlattices
Autorzy:
Gruhn, W.
Powiązania:
https://bibliotekanauki.pl/articles/1955468.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
Opis:
Using the modified total energy approach of Bruno, we prove that for the transition metal or rare-earth superlattices the additional scattering of free electrons on magnetic ion multipole moment gives rise to ferroquadrupolar biquadratic coupling between magnetic layers. We show that in this novel, intrinsic mechanism, the anisotropy of the magnetoresistivity should manifest itself.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 303-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superparamagnetic Grains as Source of Giant Magnetoresistance Effect in Discontinuous Co/Ag Multilayers
Autorzy:
Luciński, T.
Stobiecki, F.
Dubowik, J.
Czajka, R.
Powiązania:
https://bibliotekanauki.pl/articles/1955447.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
Opis:
The as-deposited and annealed Co/Ag discontinuous multilayer-like structures were examined. Discontinuous Co sublayers are thought to consist of fine superparamagnetic and ferromagnetic grains. Using the bimodal superparamagnetic grain sizes distribution the GMR(H) dependencies were successfully modelled with the use of two Langevin functions simulating the magnetization of the superparamagnetic grains.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 269-272
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
RKKY-like Biquadratic Exchange in Magnetic Superlattices
Autorzy:
Gruhn, W.
Bąk, Z.
Jaroszewicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/1945268.pdf
Data publikacji:
1996-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.70.Fr
Opis:
We show that in magnetic metallic superlattices along with the bilinear RKKY-reminiscent interaction between magnetic superlattices there can be an important quadrupole-quadrupole coupling. In an analytical way we derive the range functions of the quadrupol-quadrupole interaction and discuss its relation to magnetoresistivity.
Źródło:
Acta Physica Polonica A; 1996, 89, 3; 417-420
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lattice Misfit Strain as Origin for Biquadratic Interlayer Coupling
Autorzy:
Jaroszewicz, R.
Bąk, Z.
Gruhn, W.
Powiązania:
https://bibliotekanauki.pl/articles/1945269.pdf
Data publikacji:
1996-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.70.Fr
Opis:
The direct observations of some MBE grown superlattices show large interfacial undulations, which is attributed to the elastic relaxation of tensile layers. Assuming that the interface lateral lattice deformation, due to ionic radii misfit, is given by the periodic solution of the Frenkel-Kontorova model, we calculate the magnetoelastic contribution to the biquadratic magnetic coupling between ferromagnetic layers across the nonmagnetic spacer. We show that due to the correlated modulations of the effective bilinear exchange integral, there arises a biquadratic exchange which favours perpendicular orientations of magnetization in adjacent ferromagnetic layers.
Źródło:
Acta Physica Polonica A; 1996, 89, 3; 421-424
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Magnetostriction within Néels Model
Autorzy:
Żuberek, R.
Żymierska, D.
Szymczak, H.
Powiązania:
https://bibliotekanauki.pl/articles/1930607.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Pd
75.70.Cn
Opis:
The aim of the present paper is to determine the surface magnetostriction in the spirit of Néel's model of the surface magnetic anisotropy. Calculations have been performed for bcc and fcc ferromagnetic crystals.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 439-442
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconductor Ferromagnetic Structures
Autorzy:
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2014124.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.70.Cn
Opis:
Ferromagnetic semiconductor structures such as superlattices or trilayers form a new class of magnetic systems composed entirely of semiconductor materials. The examples are Ga$\text{}_{1-x}$Mn$\text{}_{x}$As-AlGaAs with the ferromagnetic layer of GaMnAs semimagnetic (diluted magnetic) semiconductor or EuS-PbS with the ferromagnetic member (EuS) of the family of europium chalcogenides. We discuss the spectrum of perspective ferromagnetic semiconductor materials, the effect of size and stress on magnetic properties of ultrathin semiconductor ferromagnetic layers, and the effect of interlayer exchange in all-semiconductor systems.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 171-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Coupling and Magnetization Profiles of Binary and Ternary Magnetic Multilayers
Autorzy:
Süss, F.
Krey, U.
Krompiewski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1955456.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.70.-i
Opis:
Within a spin-polarized LMTO approach in the atomic-sphere approximation we calculate ab initio the magnetic properties of various binary and ternary multilayers composed of Fe, Co, Ni, Cr, V and Cu. The emphasis lies on the indirect exchange interaction of the magnetic sandwiches across the antiferromagnetic or non-magnetic spacers, and on the profiles of the intrinsic resp. induced magnetic moments. Among other results we find (i) that Ni is very sensitive on its neighborhood and that (ii) at the interface to Fe, V gets almost as strongly polarized as Cr, whereas in the interior layers, the V sandwich remains non-polarized.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 281-284
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoelastic Effects and Magnetic anisotropy in Superlattice System
Autorzy:
Jaroszewicz, R.
Bąk, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1955483.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.70.Ak
Opis:
In this contribution, we will discuss the effect of interface misfit strain on magnetic coupling of ferromagnetic layers, across intervening, metallic spacer in the epitaxial superlattice system. We calculate the interface lateral lattice deformation, due to ionic radii misfit within the Frenkel-Kontorova model and derive its influence on surface magnetic anisotropy and electronic properties of the nonmagnetic spacer. We will study also the origin of the interface magnetoelastic asymmetry in superlattices and its effect on magnetic coupling between magnetic layers. Also the magnetoelastic contribution to the in-plane exchange coupling is widely discussed.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 325-328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
From the Co Nanocrystals to Their Self-Organizations: Towards Ferromagnetism at Room Temperature
Autorzy:
Lisiecki, I.
Powiązania:
https://bibliotekanauki.pl/articles/1490092.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
75.70.Cn
Opis:
Here, we show that rather uniform 7 nm Co nanocrystals self-organize into long-range two- and three-dimensional superlattices. Due to this ability we have to control the mesoscopic ordering; unexpected intrinsic collective chemical and physical properties have been discovered. By annealing treatment, a crystallographic transition from a polycrystalline fcc- to single crystalline hcp-Co phase is obtained leading to a drastic change in the magnetic properties such as an increase in the blocking temperature that can reach a value close to room temperature. Neither coalescence between nanocrystals nor oxidation of the Co material is observed. In these artificial solids, when the individual nanocrystal anisotropy is low, super-spin glass behavior is observed.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 426-433
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Biquadratic Interlayer Coupling in Magnetic Multilayers
Autorzy:
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1930611.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Rr
75.70.Cn
Opis:
Intrinsic biquadratic interlayer coupling in magnetic layered structures is analysed theoretically within the spin-polarized free-electron approximation. The corresponding coupling parameter oscillates with the interlayer thickness with the oscillation period equal to half of that for bilinear term. An extrinsic mechanism following from a competition between the intra- and interlayer exchange coupling is also discussed.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 461-464
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Giant Magnetoresistance in Permalloy/Copper Multilayers
Autorzy:
Luciński, T.
Stobiecki, F.
Powiązania:
https://bibliotekanauki.pl/articles/1955449.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Jt
75.70.Cn
Opis:
The oscillatory behaviour of the giant magnetoresistivity versus Cu sublayer thickness was observed in Ni$\text{}_{83}$Fe$\text{}_{17}$/Cu multilayers with an oscillation period of 1 nm independently of buffer layer and substrates used in the experiment. The giant magnetoresistance field sensitivity equal to 0.02%/Oe and 0.15%/Oe for the first and the second maximum respectively, were found. It was shown that the giant magnetoresistance effect in our multilayers is not only due to the antiferromagnetic coupling between adjacent permalloy layers but also due to the superparamagnetic-like behaviour related to the existence of the intermixed interfacial areas.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 273-275
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interface Effective Pinning and Dynamical Coupling of Spin Waves in Bilayer Ferromagnetic Films with Canted Magnetizations
Autorzy:
Puszkarski, H.
Cottam, M. G.
Powiązania:
https://bibliotekanauki.pl/articles/1887424.pdf
Data publikacji:
1991-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Ds
75.70.Cn
Opis:
We present a theory for the spin-wave excitations in bilayer magnetic systems with exchange coupling across the interface between two ferromagnetic films having the same crystallographic structure. The Hamiltonian includes exchange and anisotropy terms within each magnetic film of the composite system, as well as at the interface and at the free surfaces. We examine, in particular, the effect of interface canting between the magnetization directions for each film, and we derive effective pinning parameters and dynamic coupling parameters for the interface as functions of the canting angle. We show that, in the special case when the magnetization directions are antiparallel in the bilayer system, the two films may be considered as effectively decoupled as regards the spin-wave dynamics. We discuss the relevance of this theory to recent experimental studies of bilayer ferromagnetic systems that exhibit antiferromagnetic interface exchange.
Źródło:
Acta Physica Polonica A; 1991, 79, 4; 549-564
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Mesoporous Silica Nanocomposite for Biodiesel Production
Autorzy:
Erdem, S.
Öksüzoğlu, R.
Avşar, S.
Erdem, B.
Powiązania:
https://bibliotekanauki.pl/articles/1031299.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
88.20.fk
Opis:
Ordered mesoporous silicas can be utilized as support because of having large surface area, tunable porosity, uniform pore size distribution, high thermal stability and modifiable properties. However, these materials introduce separation problems in liquid-phase processes. We have prepared Fe₃O₄-SBA-15-SO₃H solid acid catalyst by combining the properties of a magnetic material and the mesoporous character of silica. The sulfonic acid functionalized solid acid catalyst, containing both magnetic nanoparticles and mesoporous silica, is not only separable but also stable under hydrothermal conditions, which are usually employed for biodiesel production. Esterification of oleic acid with methanol for biodiesel production was carried out effectively and 75% conversion of ester was approximately reached within six hours in the presence of Fe₃O₄-SBA-15-SO₃H magnetic solid acid catalyst. In addition, the catalyst could be separated from the reaction system by applying external magnetic field and reused without deactivation.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 763-766
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magneto-Optical and Optical Investigation of the Surface Region of Ion implanted Garnet Films
Autorzy:
Lali, Kalandadze
Powiązania:
https://bibliotekanauki.pl/articles/1387379.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
78.20.Ls
Opis:
In the present work we have shown the efficiency of complex investigation of the ion implanted garnet surface region by magneto-optical and optical methods. We have investigated the optical and magneto-optical properties of the ion-implanted (YBiCaSm)₃(FeGeSi)₅O₁₂ garnet films. It has shown that ion implantation influences significantly the magneto-optical properties of the garnet films and practically does not change its optical characteristics. We have also determined the spectral dependences of the component of the tensor of dielectric permittivity for the surface of ion implanted (YBiCaSm)₃(FeGeSi)₅O₁₂ ferrite-garnet films before and after implantation process. These calculations let us evaluate the influence of implantation on an electronic energy structure of the surface layer for the sample.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 582-584
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetization Curves of Geometrically Frustrated Exchange-Biased FM/AFM Bilayers
Autorzy:
Pankratova, M.
Žukovič, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032766.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ej
75.70.Cn
Opis:
We consider a ferromagnetic/antiferromagnetic bilayer on a triangular lattice in the framework of the classical XY model. The impact of the geometrical frustration in this system on the magnetization curves and the exchange bias phenomenon is studied. The magnetization curves and the phase diagram for such systems are obtained. We observe horizontal plateaus and a split of the hysteresis loop on the magnetization curves. It is shown that the shift of the hysteresis loop (exchange bias) occurs for the systems with a magnetically hard antiferromagnet.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 642-644
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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