67 research outputs found
Nonequilibrium statistical operators for systems with finite lifetime
A family of nonequilibrium statistical operators (NSO) is introduced which differ by the system lifetime
distribution over which the quasiequilibrium (relevant) distribution is averaged. This changes the form of
the source in the Liouville equation, as well as the expressions for the kinetic coefficients, average fluxes,
and kinetic equations obtained with use of NSO. The difference from the Zubarev form of NSO is of the order
of the reciprocal lifetime of a system
Planar SFS Josephson Junctions Made by Focused Ion Beam Etching
Superconductor-Ferromagnet-Superconductor (S-F-S) Josephson junctions were
fabricated by making a narrow cut through a S-F double layer using direct
writing by Focused Ion Beam (FIB). Due to a high resolution (spot size smaller
than 10 nm) of FIB, junctions with a small separation between superconducting
electrodes ( 30 nm) can be made. Such a short distance is sufficient for
achieving a considerable proximity coupling through a diluted CuNi ferromagnet.
We have successfully fabricated and studied S-F-S (Nb-CuNi-Nb) and S-S'-S
(Nb-Nb/CuNi-Nb) junctions. Junctions exhibit clear Fraunhofer modulation of the
critical current as a function of magnetic field, indicating good uniformity of
the cut. By changing the depth of the cut, junctions with the product
ranging from 0.5 mV to V were fabricated.Comment: 5 pages, 5 figures, presentation at EUCAS-2003, to be published in
Physica
Lifetime distributions in the methods of non-equilibrium statistical operator and superstatistics
A family of non-equilibrium statistical operators is introduced which differ
by the system age distribution over which the quasi-equilibrium (relevant)
distribution is averaged. To describe the nonequilibrium states of a system we
introduce a new thermodynamic parameter - the lifetime of a system.
Superstatistics, introduced in works of Beck and Cohen [Physica A \textbf{322},
(2003), 267] as fluctuating quantities of intensive thermodynamical parameters,
are obtained from the statistical distribution of lifetime (random time to the
system degeneracy) considered as a thermodynamical parameter. It is suggested
to set the mixing distribution of the fluctuating parameter in the
superstatistics theory in the form of the piecewise continuous functions. The
distribution of lifetime in such systems has different form on the different
stages of evolution of the system. The account of the past stages of the
evolution of a system can have a substantial impact on the non-equilibrium
behaviour of the system in a present time moment.Comment: 18 page
General Beltrami equations and BMO
We study the Beltrami equations βf = ΞΌ(z)βf + Ξ½(z)βf under the assumption that the coefficients ΞΌ, Ξ½ satisfy the inequality |ΞΌ| + |Ξ½| < 1 almost everywhere. Sufficient conditions for the existence of homeomorphic ACL solutions to the Beltrami equations are given in terms of the bounded mean oscillation by John and Nirenberg
ΠΠ΅Π»ΡΠ²ΠΈΠΎΠΌΠ΅ΡΡΠΈΡ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΏΡΠΈΠΌΠΈΠ½Π΅Π½ΠΈΡ ΡΠ΄Π΅ΡΠ½ΠΎ-ΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΡΠ΅Π·ΠΎΠ½Π°Π½ΡΠ° ΠΏΡΠΈ ΡΡΠ±ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈΡ ΡΠΎΡΠΌΠ°Ρ ΡΠ·ΠΊΠΎΠ³ΠΎ ΡΠ°Π·Π° ΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΡΠΈΡΠΊΠ° Π² ΡΠ»ΡΡΠ°Π΅ Π΄ΠΈΡΡΠΎΡΠΈΠΈ ΠΏΡΠ΅ΡΠΈΠΊΠΎΠ²
Military Medical Academy, Department of radiology, St-Petersburg, Russia, Federal Center of blood, heart and endocrinology by VA. Almazov, St-Petersburg, RussiaΠΠΎ ΠΌΠ½ΠΎΠ³ΠΈΡ
ΡΡΡΠ°Π½Π°Ρ
ΡΠΎΡΠ½ΠΎΡΡΡ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ ΡΠ°Π·ΠΌΠ΅ΡΠΎΠ² Π½Π°ΡΡΠΆΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π° ΡΠΎΠΌΠ½ΠΈΡΠ΅Π»ΡΠ½Π°. Π Π°ΡΠΏΡΠΎΡΡΡΠ°Π½Π΅Π½Π½ΠΎΡΡΡ
ΠΏΠΎΠ΄ΡΠΈΠΏΠΎΠ² ΡΡΠ±ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈ ΡΠ·ΠΊΠΎΠ³ΠΎ ΠΊΠΎΡΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π° Π΅ΡΠ΅ Π±ΠΎΠ»Π΅Π΅ Π·Π°ΡΡΡΠ΄Π½ΡΠ΅Ρ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΡ.
Π¦Π΅Π»Ρ: ΡΡΡΠ°Π½ΠΎΠ²ΠΈΡΡ Π°ΠΊΡΡΠ΅ΡΡΠΊΠΈΠ΅ ΠΠ ΠΏΠ΅Π»ΡΠ²ΠΈΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΈ ΡΠ΅ΡΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ΅ΡΠ΅ΡΠ΅Π½ΡΠ½ΡΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΡ ΠΏΡΠΈ ΠΎΡΠ΅Π½ΠΊΠ΅
ΡΠΈΡΠΊΠ° Π΄ΠΈΡΡΠΎΡΠΈΠΈ ΠΏΠ»Π΅ΡΠΈΠΊΠΎΠ² ΠΏΠ»ΠΎΠ΄Π° ΠΏΠ΅ΡΠ΅Π΄ ΡΠΎΠ΄Π°ΠΌΠΈ ΠΈ ΡΡΠ°Π²Π½ΠΈΡΡ ΠΠ ΠΏΠ΅Π»ΡΠ²ΠΈΠΎΠΌΠ΅ΡΡΠΈΡ Ρ Π½Π°ΡΡΠΆΠ½ΡΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ.
ΠΠ΅ΡΠΎΠ΄Ρ: ΠΎΠ±ΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ 40 ΠΆΠ΅Π½ΡΠΈΠ½ Ρ ΠΎΠ΄Π½ΠΎΠΏΠ»ΠΎΠ΄Π½ΠΎΠΉ Π±Π΅ΡΠ΅ΠΌΠΎΠ½Π½ΠΎΡΡΡΡ Π² ΡΡΠΎΠΊΠ΅ 38-39 Π½Π΅Π΄Π΅Π»Ρ. ΠΠ ΠΏΠ΅ΠΏΡΠ²ΠΈΠΎΠΌΠ΅ΡΡΠΈΡ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠ»Π°ΡΡ Π½Π° Π²ΡΡΠΎΠΊΠΎΠΏΠΎΠ»ΡΠ½ΠΎΠΌ 1,5 Π’ MRT. ΠΡΠ΅ ΡΡΠ±ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠΈΠΏΡ ΡΠ·ΠΊΠΎΠ³ΠΎ ΠΊΠΎΡΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π° Π±ΡΠ»ΠΈ ΡΠ°Π·Π΄Π΅Π»Π΅Π½Ρ Π½Π° 3 ΡΡΠ΅ΠΏΠ΅Π½ΠΈ. ΠΡΠΎΠ²ΠΎΠ΄ΠΈΠ»Π°ΡΡ ΡΠ°ΠΊΠΆΠ΅ ΡΠ΅ΡΠΎΠΌΠ΅ΡΡΠΈΡ. Π ΠΈΡΠΊ Π΄ΠΈΡΡΠΎΡΠΈΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ»ΡΡ ΠΊΠ°ΠΊ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΡΠΉ, Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΡΠΉ ΠΈ Π²ΡΡΠΎΠΊΠΈΠΉ.
Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ: ΠΠ±ΡΠΎΠ»ΡΡΠ½ΠΎ ΡΠ·ΠΊΠΈΠΉ ΡΠ°Π· Π±ΡΠ» Π²ΡΡΠ²Π»Π΅Π½ Ρ 3 ΠΆΠ΅Π½ΡΠΈΠ½. ΠΠΈΠ°ΠΌΠ΅ΡΡ ΠΊΠΎΡΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π°, ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½Π½ΡΠΉ Π½Π° ΠΠ Π’,
Π±ΡΠ» Π½ΠΎΡΠΌΠ°Π»ΡΠ½ΡΠΌ Ρ 14 (35%) ΠΆΠ΅Π½ΡΠΈΠ½. ΠΠ²Π΅Π½Π°Π΄ΡΠ°ΡΠΈ ΠΆΠ΅Π½ΡΠΈΠ½Π°ΠΌ (30%) ΡΠΎ 2 ΡΡΠ΅ΠΏΠ΅Π½ΡΡ ΡΠ·ΠΊΠΎΠ³ΠΎ ΡΠ°Π·Π° ΠΈ/ΠΈΠ»ΠΈ ΠΊΡΡΠΏΠ½ΡΠΌ
ΠΏΠ»ΠΎΠ΄ΠΎΠΌ (>4000 Π³) ΠΏΡΠΈ ΠΎΡΡΡΡΡΡΠ²ΠΈΠΈ Π΄ΡΡΠ³ΠΈΡ
ΠΏΡΠΎΡΠΈΠ²ΠΎΠΏΠΎΠΊΠ°Π·Π°Π½ΠΈΠΉ Π±ΡΠ»ΠΎ ΡΠ΅ΠΊΠΎΠΌΠ΅Π½Π΄ΠΎΠ²Π°Π½ΠΎ ΡΠΎΠ΄ΠΎΡΠ°Π·ΡΠ΅ΡΠ΅Π½ΠΈΠ΅ ΡΠ΅ΡΠ΅Π· Π΅ΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ ΡΠΎΠ΄ΠΎΠ²ΡΠ΅ ΠΏΡΡΠΈ, Π½ΠΎ 6 ΠΈΠ· Π½ΠΈΡ
Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΎ ΠΠ‘.
ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅: Π½ΠΈΠ·ΠΊΠ°Ρ ΡΠ°ΡΡΠΎΡΠ° Π²ΡΡΠ²Π»Π΅Π½ΠΈΡ ΡΡΠ±ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈ ΡΠ·ΠΊΠΎΠ³ΠΎ ΠΊΠΎΡΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π° ΠΏΡΠΈ Π½Π°ΡΡΠΆΠ½ΡΡ
ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡΡ
ΠΌΠΎΠΆΠ΅Ρ ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡΡ ΠΊ Π·Π°ΠΏΠΎΠ·Π΄Π°Π»ΠΎΠΉ ΠΈΠ½ΡΡΠ°Π½Π°ΡΠ°Π»ΡΠ½ΠΎΠΉ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ ΡΡΠΎΠΉ ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ. ΠΠ ΠΏΠ΅Π»ΡΠ²ΠΈΠΎΠΌΠ΅ΡΡΠΈΡ Π²ΡΡΠ²Π»ΡΠ»Π°
ΡΡΠ±ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΡΠΆΠ΅Π½ΠΈΠ΅ ΠΊΠΎΡΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π°. ΠΠΎΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»ΡΠ½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅ ΡΠ΅ΡΠΎΠΌΠ΅ΡΡΠΈΠΈ ΠΏΠΎΠΌΠΎΠ³Π»ΠΈ ΠΎΡΠ΅Π½ΠΈΡΡ ΡΠΈΡΠΊ Π΄ΠΈΡΡΠΎΡΠΈΠΈ ΠΏΠ»Π΅ΡΠΈΠΊΠΎΠ² ΠΏΠ΅ΡΠ΅Π΄ ΡΠΎΠ΄Π°ΠΌΠΈ
Andreev conductance of a domain wall
At low temperatures, the transport through a superconductor-ferromagnet
tunnel interface is due to tunneling of electrons in pairs. Exchange field of a
monodomain ferromagnet aligns electron spins and suppresses the two electron
tunneling. The presence of the domain walls at the SF interface strongly
enhances the subgap current. The Andreev conductance is proven to be
proportional to the total length of domain walls at the SF interface.Comment: 4 pages and 1 figur
Magnetization Dynamics in Proximity-Coupled Superconductor-Ferromagnet-Superconductor Multilayers:II. Thickness Dependence of the Superconducting Torque
In this work, we study magnetization dynamics in superconductor-ferromagnet-superconductor thin-film structures. Results of the broad-band ferromagnetic resonance spectroscopy are reported for a large set of samples with varied thickness of both superconducting and ferromagnetic layers in a wide frequency, field, and temperature ranges. Experimentally the one-dimensional anisotropic action of superconducting torque on magnetization dynamics is established; its dependence on thickness of layers is revealed. It is demonstrated that experimental findings support the recently proposed mechanism of the superconducting torque formation via the interplay between the superconducting imaginary conductance and magnetization precession at superconductor-ferromagnet interfaces. Microwave spectroscopy studies in this work are supplemented by investigations of the crystal structure and the microstructure of studied multilayers.</p
Inhomogeneous magnetism induced in a superconductor at superconductor-ferromagnet interface
We study a magnetic proximity effect at superconductor (S) - ferromagnet (F)
interface. It is shown that due to an exchange of electrons between the F and S
metals ferromagnetic correlations extend into the superconductor, being
dependent on interface parameters. We show that ferromagnetic exchange field
pair breaking effect leads to a formation of subgap bands in the S layer local
density of states, that accommodate only one spin-polarized quasiparticles.
Equilibrium magnetization leakage into the S layer as function of SF interface
quality and a value of ferromagnetic interaction have also been calculated. We
show that a damped-oscillatory behavior versus distance from SF interface is a
distinguished feature of the exchange-induced magnetization of the S layer.Comment: 10 pages, 7 Postscript figure
Periodic alternating -junction structures as realization of -Josephson junctions
We consider the properties of a periodic structure consisting of small
alternating 0- and pi- Josephson junctions. We show that depending on the
relation between the lengths of the individual junctions, this system can be
either in the homogeneous or in the phase-modulated state. The modulated phase
appears via a second order phase transition when the mismatch between the
lengths of the individual junctions exceeds the critical value. The screening
length diverges at the transition point. In the modulated state, the
equilibrium phase difference in the structure can take any value from -pi to pi
(phi-junction). The current-phase relation in this structure has very unusual
shape with two maxima. As a consequence, the field dependence of the critical
current in a small structure is very different from the standard Fraunhofer
dependence. The Josephson vortex in a long structure carries partial magnetic
flux, which is determined by the equilibrium phase.Comment: 4 pages, 3 figues, submitted to Phys. Rev.
Minigap in a long disordered SNS junction: analytical results
We review and refine analytical results on the density of states in a long
disordered superconductor - normal-metal - superconductor junction with
transparent interfaces. Our analysis includes the behavior of the minigap near
phase differences zero and PI across the junction, as well as the density of
states at energies much larger than the minigap but much smaller than the
superconducting gap.Comment: 4 page
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