Title :
Strain and grain connectivity in Bi2223/Ag superconducting tapes
Author :
Ying Kai Huang ; Ten Haken, B. ; ten Kate, H.H.J.
Author_Institution :
Fac. of Appl. Phys., Twente Univ., Enschede, Netherlands
fDate :
6/1/1999 12:00:00 AM
Abstract :
The critical current reduction in silver-sheathed (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ superconducting tapes (Bi2223/Ag) is investigated when loaded with uni-axial strains in combination with a magnetic field perpendicular to the tape surface. The number and quality of the grain-to-grain connections and the alignment of the superconducting cores mainly determine the critical current in Bi2223/Ag tapes. It is assumed that the transport current flows simultaneously through two current carrying paths in the tape: one through the network of Josephson junctions and the other is through the well-connected grains. The model describes well the magnetic field dependence of the critical current at various strains. A detailed analysis has shown that strain deteriorates grain connectivity, induces cracking and hence changes the current carrying path. Furthermore, strain may introduce new defects inside the grains along the strong-link current path and increase intra-granular pinning strength.
Keywords :
bismuth compounds; calcium compounds; composite superconductors; critical current density (superconductivity); crystal microstructure; high-temperature superconductors; internal stresses; lead compounds; silver; strontium compounds; superconducting tapes; (BiPb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/; Ag; Bi2223/Ag superconducting tapes; HTSC; Josephson junctions; cracking; critical current reduction; current carrying path; defects; grain connectivity; intra-granular pinning strength; magnetic field dependence; silver-sheathed (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ superconducting tapes; strain; strong-link current path; transport current; Capacitive sensors; Critical current; Josephson junctions; Magnetic field induced strain; Magnetic field measurement; Mechanical factors; Strain measurement; Superconducting films; Superconducting materials; Tensile strain;
Journal_Title :
Applied Superconductivity, IEEE Transactions on