نتایج جستجو برای: granular superconductor

تعداد نتایج: 34207  

2014
Rong-Gen Cai Li Li

We study in detail the phase structure of a holographic p-wave superconductor model in a five dimensional Einstein-Maxwell-complex vector field theory with a negative cosmological constant. To construct complete phase diagrams of the model, we consider both the soliton and black hole backgrounds. In both two cases, there exist second order, first order and zeroth order phase transitions, and th...

2013
V Heera J Fiedler R Hübner B Schmidt M Voelskow W Skorupa R Skrotzki T Herrmannsdörfer J Wosnitza M Helm

Si films sputter deposited on thermally oxidized Si are enriched with Ga by ion implantation through a SiO2 capping layer. The morphology and the electrical transport properties of these films are investigated after rapid thermal annealing. Amorphous, Ga-rich nanoinclusions are embedded in a nanocrystalline Si matrix. The metallic nanoinclusions become superconducting below 7K. They form a rand...

1998
Mauricio Barahona Shinya Watanabe

When magnetic flux moves across layered or granular superconductor structures, the passage of vortices can take place along channels which develop finite voltage, while the rest of the material remains in the zero-voltage state. We present analytical studies of an example of such mixed dynamics: the row-switched (RS) states in underdamped two-dimensional Josephson arrays, driven by a uniform DC...

In this research, the effect of addition of silicon carbide (SiC) nanoparticles on the improvement of the structural, superconductivity, magnetic, and flux pinning properties of high-temperature superconductor Bi1.6Pb0.4Sr2Ca2Cu3O10+θ (Bi-2223) was investigated. The Bi-2223 ceramic superconductor was prepared using the sol-gel method, and silicon carbide nanoparticles were modified by Azobisiso...

2008
Luzi Bergamin Dario Izzo

We critically review our recent claims that it is possible to obtain a propellantless propulsion device similar to electrodynamic tethers by means of a closed wire partially shielded by a superconductor from the outer magnetic field. We find that such a device is not possible as it violates basic physical laws. Furthermore, we show what is the correct local picture for the currents distribution...

2008
W. C. Chan P. Yang

A modified close cycle helium gas cryogenic system was used to measure the flux drag torque acting on a free spinning disk magnet by a single grain YBCO superconductor. It was found that at low spinning speed ( less than 8 Hz ) and constant levitation height, the flux drag torque decreased with temperature which behavior is roughly similar to the temperature dependence of the reciprocal of crit...

2004
Jan Petter Morten Arne Brataas Wolfgang Belzig

We employ the Keldysh formalism in the quasiclassical approximation to study transport in a diffusive superconductor. The resulting 434 transport equations describe the flow of charge and energy as well as the corresponding flow of spin and spin energy. Spin-flip scattering due to magnetic impurities is included. We find that the spin-flip length is renormalized in the superconducting case and ...

Journal: :Physical review letters 1996
Blatter Feigel'man Geshkenbein Larkin van Otterlo A

In a type II superconductor the gap variation in the core of a vortex line induces a local charge modulation. Accounting for metallic screening, we determine the line charge of individual vortices and calculate the electric field distribution in the half space above a field penetrated superconductor. The resulting field is that of an atomic size dipole d ∼ eaBẑ, aB = h̄/me is the Bohr radius, ac...

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