140 research outputs found
Universal conductance fluctuations and low temperature 1/f noise in mesoscopic AuFe spin glasses
We report on intrinsic time-dependent conductance fluctuations observed in
mesoscopic AuFe spin glass wires. These dynamical fluctuations have a 1/f-like
spectrum and appear below the measured spin glass freezing temperature of our
samples. The dependence of the fluctuation amplitude on temperature, magnetic
field, voltage and Fe concentration allows a consistent interpretation in terms
of quantum interference effects which are sensitive to the slowly fluctuating
spin configuration.Comment: 4 pages, 4 figure
Magnetic-domain-controlled vortex pinning in a superconductor/ferromagnet bilayer
Vortex pinning in a type-II superconducting Pb film covering a Co/Pt
multilayer with perpendicular magnetic anisotropy is investigated. Different
stable magnetic domain patterns like band and bubble domains can be created in
the Co/Pt multilayer, clearly influencing the vortex pinning in the
superconducting Pb layer. Most effective pinning is observed for the bubble
domain state. We demonstrate that the pinning properties of the
superconductor/ferromagnet bilayer can be controlled by tuning the size,
density and magnetization direction of the bubbles.Comment: 4 pages, 3 figures, accepted for AP
Flux Jumps Driven by a Pulsed Magnetic Field
The understanding of flux jumps in the high temperature superconductors is of
importance since the occurrence of these jumps may limit the perspectives of
the practical use of these materials. In this work we present the experimental
study of the role of heavy ion irradiation in stabilizing the HTSC against flux
jumps by comparing un-irradiated and 7.5 10^10 Kr-ion/cm2 irradiated
(YxTm1-x)Ba2Cu3O7 single crystals. Using pulsed field magnetization
measurements, we have applied a broad range of field sweep rates from 0.1T/s up
to 1800 T/s to investigate the behavior of the flux jumps. The observed flux
jumps, which may be attributed to thermal instabilities, are incomplete and
have different amplitudes. The flux jumps strongly depend on the magnetic
field, on the magneto-thermal history of the sample, on the magnetic field
sweep rate, on the critical current density jc, on the temperature and on the
thermal contact with the bath in which the sample is immersed.Comment: 5 pages, PDF-fil
Management of sustainable organizational development of large-scale economic systems
Π£ ΡΡΠ°ΡΡ Π²ΠΈΠ·Π½Π°ΡΠ΅Π½ΠΎ Π½Π΅ΠΎΠ±Ρ
ΡΠ΄Π½ΡΡΡΡ Π²Π΄ΠΎΡΠΊΠΎΠ½Π°Π»Π΅Π½Π½Ρ ΡΠΈΡΡΠ΅ΠΌΠΈ ΡΠΏΡΠ°Π²Π»ΡΠ½Π½Ρ ΠΎΡΠ³Π°Π½ΡΠ·Π°ΡΡΠΉΠ½ΠΎ-Π΅ΠΊΠΎΠ½ΠΎΠΌΡΡΠ½ΠΈΠΌ ΠΌΠ΅Ρ
Π°Π½ΡΠ·ΠΌΠΎΠΌ Π·Π°Π±Π΅Π·ΠΏΠ΅ΡΠ΅Π½Π½Ρ Π΅ΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡ ΠΎΡΠ³Π°Π½ΡΠ·Π°ΡΡΡ ΡΠ° ΡΡΡΠΉΠΊΠΎΠ³ΠΎ ΠΎΡΠ³Π°Π½ΡΠ·Π°ΡΡΠΉΠ½ΠΎΠ³ΠΎ ΡΠΎΠ·Π²ΠΈΡΠΊΡ ΠΏΡΠ΄ΠΏΡΠΈΡΠΌΡΡΠ²Π°; Π½Π°Π²Π΅Π΄Π΅Π½ΠΎ ΠΏΠ΅ΡΠ΅Π²Π°Π³ΠΈ Π²Π΅Π»ΠΈΠΊΠΎΠΌΠ°ΡΡΡΠ°Π±Π½ΠΈΡ
Π΅ΠΊΠΎΠ½ΠΎΠΌΡΡΠ½ΠΈΡ
ΡΠΈΡΡΠ΅ΠΌ ΠΏΠ΅ΡΠ΅Π΄ ΡΠ½ΡΠΈΠΌΠΈ ΠΎΡΠ³Π°Π½ΡΠ·Π°ΡΡΠΉΠ½ΠΈΠΌΠΈ ΡΠΎΡΠΌΠ°ΠΌΠΈ; ΡΠΎΠ·Π³Π»ΡΠ½ΡΡΠΎ ΠΏΠΎΠ½ΡΡΡΡ "ΡΠΎΠ·Π²ΠΈΡΠΎΠΊ" ΡΠ° ΠΌΠΎΠ΄Π΅Π»Ρ ΠΆΠΈΡΡΡΠ²ΠΎΠ³ΠΎ ΡΠΈΠΊΠ»Ρ Π²Π΅Π»ΠΈΠΊΠΎΠΌΠ°ΡΡΡΠ°Π±Π½ΠΈΡ
Π΅ΠΊΠΎΠ½ΠΎΠΌΡΡΠ½ΠΈΡ
ΡΠΈΡΡΠ΅ΠΌ.The article defines the necessity of improving the management system of the organizational and economic mechanism for ensuring an effective organization and sustainable organizational development of the enterprise; also there were presented advantages of large-scale economic systems over other organizational forms; the concept of "development" and the life cycle model of large-scale economic systems are considered
Confinement and Quantization Effects in Mesoscopic Superconducting Structures
We have studied quantization and confinement effects in nanostructured
superconductors. Three different types of nanostructured samples were
investigated: individual structures (line, loop, dot), 1-dimensional (1D)
clusters of loops and 2D clusters of antidots, and finally large lattices of
antidots. Hereby, a crossover from individual elementary "plaquettes", via
clusters, to huge arrays of these elements, is realized. The main idea of our
study was to vary the boundary conditions for confinement of the
superconducting condensate by taking samples of different topology and, through
that, modifying the lowest Landau level E_LLL(H). Since the critical
temperature versus applied magnetic field T_c(H) is, in fact, E_LLL(H) measured
in temperature units, it is varied as well when the sample topology is changed
through nanostructuring. We demonstrate that in all studied nanostructured
superconductors the shape of the T_c(H) phase boundary is determined by the
confinement topology in a unique way.Comment: 28 pages, 19 EPS figures, uses LaTeX's aipproc.sty, contribution to
Euroschool on "Superconductivity in Networks and Mesoscopic Systems", held in
Siena, Italy (8-20 september 1997
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