Title :
Irreversibility line and flux flow noise in superconducting Nb-Ta
Author :
Otabe, E.S. ; Matsushita, T. ; Matsuno, T. ; Yamafuji, K.
Author_Institution :
Dept. of Comput. Sci. & Electron., Kyushu Inst. of Technol., Iizuka, Japan
fDate :
3/1/1991 12:00:00 AM
Abstract :
It has been found that the critical current density, J c, in high-Tc oxide superconductors is reduced to zero at high temperatures and/or high magnetic fields even in a superconducting region. The irreversibility line was investigated in weakly pinned superconducting Nb-Ta with low Tc and was compared with that in oxide superconductors. Large flux flow noise with a peak around 0.3 Hz was observed in Nb-Ta specimens. The noise power integrated in the frequency range of 0.1-1.0 Hz had a sharp peak, when it was plotted against the magnetic field. The mechanism of such a characteristic noise is examined
Keywords :
critical current density (superconductivity); flux flow; niobium alloys; noise; tantalum alloys; type II superconductors; 0.1 to 1.0 Hz; characteristic noise; critical current density; flux flow noise; irreversibility line; noise power; oxide superconductors; sharp peak; weakly pinned superconducting Nb-Ta; Critical current density; Frequency; High temperature superconductors; Magnetic field measurement; Magnetic fields; Magnetic noise; Superconducting device noise; Superconductivity; Temperature dependence; Temperature distribution;
Journal_Title :
Magnetics, IEEE Transactions on
