458 research outputs found
Josephson junction between anisotropic superconductors
The sin-Gordon equation for Josephson junctions with arbitrary misaligned
anisotropic banks is derived. As an application, the problem of Josephson
vortices at twin planes of a YBCO-like material is considered. It is shown that
for an arbitrary orientation of these vortices relative to the crystal axes of
the banks, the junctions should experience a mechanical torque which is
evaluated. This torque and its angular dependence may, in principle, be
measured in small fields, since the flux penetration into twinned crystals
begins with nucleation of Josephson vortices at twin planes.Comment: 6 page
Self-Organized Criticality Effect on Stability: Magneto-Thermal Oscillations in a Granular YBCO Superconductor
We show that the self-organized criticality of the Bean's state in each of
the grains of a granular superconductor results in magneto-thermal oscillations
preceding a series of subsequent flux jumps. We find that the frequency of
these oscillations is proportional to the external magnetic field sweep rate
and is inversely proportional to the square root of the heat capacity. We
demonstrate experimentally and theoretically the universality of this
dependence that is mainly influenced by the granularity of the superconductor.Comment: submitted to Physical Review Letters, 4 pages, RevTeX, 4 figures
available as uufile
Josephson Vortex Bloch Oscillations: Single Pair Tunneling Effect
We consider the Josephson vortex motion in a long one--dimensional Josephson
junction in a thin film. We show that this Josephson vortex is similar to a
mesoscopic capacitor. We demonstrate that a single Cooper pair tunneling
results in nonlinear Bloch--type oscillations of a Josephson vortex in a
current-biased Josephson junction. We find the frequency and the amplitude of
this motion.Comment: 7 pages, 2 figures included as postscript files, LaTe
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