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Wyszukujesz frazę "85.75.-d" wg kryterium: Temat


Tytuł:
Why Ferromagnetic Semiconductors?
Autorzy:
Dietl, T.
Powiązania:
https://bibliotekanauki.pl/articles/2030392.pdf
Data publikacji:
2001-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
72.25.Dc
75.30.Hx
85.75.-d
Opis:
Rapid development of information technologies originates from the exponential increase in the density of information that can be processed, stored, and transferred by the unit area of relevant devices. There is, however, a growing amount of evidences that the progress achieved in this way approaches its limits. Various novel ideas put forward to circumvent barriers ahead are described. Particular attention is paid to those concepts which propose to exploit electron or nuclear spins as the information carriers. Here, ferromagnetic semiconductors of III-V or II-VI compounds containing a sizable concentration of transition metals appear as outstanding spintronic materials.
Źródło:
Acta Physica Polonica A; 2001, 100, Supplement; 139-151
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dyakonov--Perel Spin Relaxation Suppressed by an Applied Magnetic Field
Autorzy:
Wilamowski, Z.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/2036865.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Rb
73.21.Fg
85.75.-d
Opis:
We observe a strong anisotropy of spin relaxation and a decrease in the spin relaxation rate with increasing electron mobility in contrast to predictions of the classical D'yakonov-Perel spin relaxation model. We show that for high electron mobility the cyclotron motion causes an additional modulation of spin-orbit coupling, leading to an effective suppression of the spin relaxation rate.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 671-674
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bychkov-Rashba Effect and g-Factor Tuning in Modulation Doped SiGe Quantum Wells
Autorzy:
Malissa, H.
Jantsch, W.
Mühlberger, M.
Schäffler, F.
Wilamowski, Z.
Draxler, M.
Bauer, P.
Powiązania:
https://bibliotekanauki.pl/articles/2038126.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.Fg
85.75.-d
Opis:
We investigate the spin resonance of electrons in one-sided modulation doped Si$\text{}_{1-x}$Ge$\text{}_{x}$ (x=0-10%)) quantum wells defined by Si$\text{}_{0.75}$Ge$\text{}_{0.25}$ barriers. In such structures, the Bychkov-Rashba effect induces an effective magnetic field in the quantum well layer which causes anisotropy of both the g-factor and the spin coherence time. Evaluation of the Rashba coefficient as a function of x yields a monotonic increase. For x=5% the shift in the resonance field exceeds the ESR linewidth already, demonstrating the possibility to use this effect for g-factor tuning to select individual spins in an ensemble.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 585-590
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Dependent Tunneling in a Magnetic Field for Junctions Involving Normal and Superconducting CDW Metals
Autorzy:
Ekino, T.
Gabovich, A. M.
Suan Li, Mai
Pękała, M.
Szymczak, H.
Voitenko, A. I.
Powiązania:
https://bibliotekanauki.pl/articles/2046730.pdf
Data publikacji:
2006-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.45.Lr
74.50.+r
85.75.-d
Opis:
The voltage, V, dependences of the differential tunnel conductance G(V) were calculated for two kinds of junctions involving normal and superconducting charge-density-wave metals (CDWMs) in the external magnetic field H. The first is a non-symmetrical junction with a CDWM electrode being biased with respect to a ferromagnet. Calculations show that the paramagnetic splitting occurs between spin-up and spin-down components of G(V), similar to what is observed when a superconducting electrode is used instead of the CDWM one. The second setup is symmetric (CDWM-I-CDWM), where I denotes an insulator. If at least one of the CDWM electrodes is normal and H≠0, G(V) will also be spin-split.
Źródło:
Acta Physica Polonica A; 2006, 109, 4-5; 477-484
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetic Resonance Study of Exchange Coupled (Ga,Mn)As/GaAs/(Ga,Mn)As Heterostructures
Autorzy:
Dziatkowski, K.
Ge, Z.
Liu, X.
Furdyna, J. K.
Clerjaud, B.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047381.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.Cn
75.30.Et
85.75.-d
Opis:
Ferromagnetic resonance study of the exchange coupled (Ga,Mn)As/ GaAs/(Ga,Mn)As heterostructures is reported. The measurements were performed on the series of samples with varying thicknesses d$\text{}_{GaAs}$ of nonmagnetic GaAs spacer, established d$\text{}_{GaAs}$-dependent extent of weak and strong interlayer exchange coupling, judging on the observation of one or two ferromagnetic resonance modes.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 227-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Limitations in the Tunability of the Spin Resonance of 2D Electrons in Si by an Electric Current
Autorzy:
Wilamowski, Z.
Malissa, H.
Glazov, M.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/2047703.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.75.-d
73.63.Hs
75.75.+a
76.30.-v
Opis:
We analyse the recently observed effect of an in-plane electric current through a Si quantum well on the conduction electron spin resonance. We find that the ratio of resonance shift and current density is independent of temperature and dissipation processes, but the channel current is reduced due to a parallel electric channel in heavily modulation doped samples. The inhomogeneous current distribution results in some broadening of the ESR line width. In high mobility Si/SiGe layers the current induced increase in the electron temperature is considerably larger than the increase in the lattice temperature. The signal amplitude scales with the square of electron mobility.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 375-379
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Planar Hall Effect in Ferromagnetic (Ga,Mn)As/GaAs Superlattices
Autorzy:
Wesela, W.
Wosiński, T.
Mąkosa, A.
Figielski, T.
Sadowski, J.
Terki, F.
Charar, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047701.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.50.Jt
75.50.Pp
75.30.Gw
85.75.-d
Opis:
The planar Hall effect was used for investigation of magnetic anisotropy in short period (Ga,Mn)As/GaAs superlattices epitaxially grown on (001) oriented GaAs substrate. The results confirmed the existence of low-temperature magnetocrystalline anisotropy in the superlattices with the easy magnetic axes directed along the two in-plane 〈100〉 directions. Attention is paid to the two-state behaviour of the planar Hall resistance at zero magnetic field that provides its usefulness for applications in non-volatile memory devices.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 369-373
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Resonance Absorption in a 2D Electron Gas
Autorzy:
Ungier, W.
Jantsch, W.
Wilamowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2047694.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.75.-d
73.63.Hs
75.75.+a
76.30.-v
Opis:
We analyze the power absorption at electron spin resonance excited by the Bychkov-Rashba spin-orbit field in a 2D electron gas. We show that, as long as the absorbed power is dissipated by the usual spin lattice relaxation mechanisms, the resonance line shape is expected to be of pure absorption type, i.e., it can be described by the imaginary part of the dynamic magnetic susceptibility. Therefore, the Dysonian line shape observed in ESR of 2D electron gas cannot result from this type of the resonance signal.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 345-350
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Polarized Current in Coulomb Blockade and Kondo Regime
Autorzy:
Ogrodnik, P.
Świrkowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047683.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
85.75.-d
Opis:
Spin-polarized electron transport through a single-level quantum dot attached to ferromagnetic and non-magnetic leads is studied with the use of the non-equilibrium Green function technique. Current polarization is investigated in dependence on parameters which characterize the device: the lead's polarization, a position of the dot energy level compared to the Fermi level in electrodes, and the Zeeman splitting of the dot level in an external magnetic field applied to the dot. Calculations were performed in two transport regimes: the Coulomb blockade regime with correlation effects treated within the Hartree-Fock approximation and the Kondo regime with a more rigorous approach to many-body effects at low temperatures.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 295-300
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lateral Spin Diffusion Probed by Two-Color Hanle-MOKE Technique
Autorzy:
Quast, J.
Astakhov, G.
Ossau, W.
Molenkamp, L.
Heinrich, J.
Höfling, S.
Forchel, A.
Powiązania:
https://bibliotekanauki.pl/articles/1811976.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Dc
72.25.Fe
85.75.-d
72.25.Rb
Opis:
We report on all optical spatially resolved spin diffusion experiments in an unstrained, unbiased n-GaAs layer. Optical pump and probe intensities are varied over a wide range to study the impact of optical disturbance on spin transport. Both quantities have a considerable influence on the measured spin diffusion length and spin lifetime. Furthermore, an effective spin diffusion coefficient was obtained as a function of temperature.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1311-1316
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Conductance of the Quantum Wire
Autorzy:
Dargys, A.
Powiązania:
https://bibliotekanauki.pl/articles/1813319.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Nm
85.35.Be
85.75.-d
Opis:
Spin transport in a semiconducting quantum wire connected to two spin-unpolarized electron reservoirs is investigated. The spin-orbit interaction is included via the Rashba Hamiltonian which together with the Zeeman Hamiltonian determines spin-filtering properties of the wire. The spin current as a function of the voltage was found to have an oscillatory or growing character.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 937-942
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Polarized Transport through Quantum Dots in the Cotunneling Regime
Autorzy:
Weymann, I.
Powiązania:
https://bibliotekanauki.pl/articles/1813873.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.63.Kv
85.75.-d
73.23.Hk
Opis:
The spin-polarized transport through two-level quantum dots weakly coupled to ferromagnetic leads is considered theoretically in the Coulomb blockade regime. It is assumed that the dot is doubly occupied, so that the current flows due to cotunneling through singlet and triplet states of the dot. It is shown that, by sweeping the bias voltage, one can induce a singlet-triplet transition, which depends on the magnetic configuration of the system and leads to nontrivial bias dependence of both the differential conductance and tunnel magnetoresistance.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 529-532
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bistability of (Ga,Mn)As Ferromagnetic Nanostructures Due to the Domain Walls Switching
Autorzy:
Andrearczyk, T.
Wosiński, T.
Mąkosa, A.
Figielski, T.
Wróbel, J.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791342.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.50.Jt
75.50.Pp
75.30.Gw
75.60.Ch
85.75.-d
Opis:
We designed and investigated four-arm nanostructures, composed of two perpendicularly crossed stripes, fabricated from ferromagnetic (Ga,Mn)As layer by means of electron-beam lithography patterning and chemical etching. The nanostructures exhibit a bistable resistance behavior resulting from two configurations of magnetic domain walls in the central part of the structures. We demonstrate a possibility of switching between two stable resistance states in zero magnetic field by applying a pulse of either weak magnetic field or electric current through the structure.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 901-903
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Current-Induced Magnetic Dynamics in Asymmetric Ferromagnetic Single-Electron Devices
Autorzy:
Kowalik, M.
Powiązania:
https://bibliotekanauki.pl/articles/1810537.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.-b
73.23.Hk
85.75.-d
Opis:
The theoretical calculations of possible dynamics for a localized magnetic moment of the central electrode in ferromagnetic single-electron devices are presented. The spin-transfer torque from spin current absorbed by the central electrode is calculated. Thereafter, an in-plane component of spin torque is regarded during the integration of the Landau-Lifshitz-Gilbert equation and the time evolution of the localized magnetic moment of the central electrode is obtained. The necessary conditions for switching of the magnetic moment are discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 290-292
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MHD Flow-Control for Hypersonic Flight
Autorzy:
Petit, J.
Geffray, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807963.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.30.Jr
47.40.Ki
47.65.-d
47.85.lb
52.30.Cv
52.75.Fk
Opis:
At the beginning of the seventies, experimental research using short duration supersonic shock driven wind tunnel were conducted and showed the efficiency of Lorentz force action on supersonic (Mach 1.4) dense (1 bar) low magnetic Reynolds number hot (10 000 K) argon flows. When working as a generator, the linear Faraday MHD converter was efficient enough, due to high electrical conductivity (3000 S/m) to create a front shock wave at the intake of the constant cross-section MHD converter. Accelerations up to 5000 m/s were obtained in 10 cm long channels. This suggested the possibility to achieve complete shock wave and turbulent wake cancellation, through MHD bypass concept. Such work gave publications in peer-reviewed journals and presentation in international MHD meetings (French Academy of Sciences 1970, Moscow 1983, Tsukuba 1986, Beijing 1992). The work was conducted both through computational simulations (based on the method of characteristics) and hydraulic simulation experiments. We present the synthesis of such studies through a project of a hypersonic vehicle based on an MHD bypass concept, landing under its own steam, using classical turbojets. Then, at Mach 3 and high altitude, MHD controlled inlets are opened. A wall converter slows down the hypersonic incoming air flow, without excessive heating, feeding a ramjet system. The subsequent electric power provides an additional impulse to the flow in the exhaust section. Cruise Mach number: 12. Local Hall parameter regime produces high voltage that, sent to the leading edges, creates a plasma cushion which prevents too high thermal flux. Lift is provided by wave riding technique. Additional rocket propeller could transform it as a reusable space launcher.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1149-1151
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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