Volume 35, Issue 11, November 2009
Index of content:
- SUPERCONDUCTIVITY, INCLUDING HIGH-TEMPERATURE SUPERCONDUCTIVITY
35(2009); http://dx.doi.org/10.1063/1.3266910View Description Hide Description
The composition of synthesized ceramic samples is investigated by x-ray phase analysis, and it is established that they are high-superconducting. It is found that the crystal structure is preserved. To investigate how the superconductivity of Bi–Sr–Ca–Cu–O is influenced by the substitution of calcium by zinc, measurements of the temperature dependence of the resistivity,thermal conductivity, and thermopower (Siebeck coefficient) are carried out. It is found that the substituted compound retains its superconducting properties . It is shown that substitution of Ca by Zn leads to an increase of the thermal conductivity. While the thermopower of shows -type conductivity in the whole range of temperatures investigated, in the type of the conductivity is changed to -type.
Influence of magnetic field on the thermal conductivity of in the superconducting phase transition region35(2009); http://dx.doi.org/10.1063/1.3266911View Description Hide Description
A study of the influence of magnetic field on the thermal conductivity of is made. It is found that the thermal conductivity increases under the influence of magnetic field because the electronic part of the thermal conductivity increases on account of breaking of the Cooper pairs and a decrease of the phonon-vortex scattering.
35(2009); http://dx.doi.org/10.1063/1.3266913View Description Hide Description
The influence of a microwave field on the resistive state brought on in a wide film by the passage of a dccurrent is investigated experimentally. In this situation the resistivity arises as a consequence of two processes: the motion of Pearl–Abrikosov vortices of the self-magnetic field of the current, and phase slip of the superconducting order parameter. It is shown that under microwave irradiation the resistivity of the film due to the vortex mechanism decreases, and at high power levels it vanishes, and then the resistivity of the film is due solely to phase slip processes, as in narrow vortex-free channels. It is found experimentally that, starting at some power level , the electromagnetic field plays a governing role in the processes giving rise to phase-slip lines. A similar conclusion is reached from a study of the influence of a microwave field on the differential resistance of a phase-slip center in narrow vortex-free channels; this suggests that phase-slip processes in wide and narrow films share a common nature.
35(2009); http://dx.doi.org/10.1063/1.3266914View Description Hide Description
The local quasiparticledensity of states in the current-carrying -wave superconducting structures is studied theoretically. The density of states can be accessed through the conductance of the scanning tunneling microscope. Two particular situations are considered: the current state of a homogeneous film, and a weak link between two current-carrying -wave superconductors.