Title :
Effective activation energy in the Bi-Sr-Ca-Cu-O systems
Author :
Sengupta, S. ; Shi, D. ; Wang, Z. ; Smith, M. ; McGinn, P.J.
Author_Institution :
Argonne Nat. Lab., IL, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
Magnetic relaxation in the Bi-Sr-Ca-Cu-O systems was investigated over a wide temperature regime. Previously reported studies of the effective activation energy, U, have been controversial in terms of temperature and field dependence of the critical current density, j/sub c/. The authors considered the temperature dependence of j/sub c/ and constructed the U-j (or M) curves for the Bi-Sr-Ca-Cu-O system. They found that at a constant driving force and temperature, U is considerably higher for 2245 samples than for 2223 samples. This enhancement can be attributed to the flux pinning from finely dispersed calcium- and copper-rich precipitates.<>
Keywords :
bismuth compounds; calcium compounds; critical current density (superconductivity); flux pinning; high-temperature superconductors; strontium compounds; Bi-Sr-Ca-Cu-O; critical current density; effective activation energy; flux pinning; high temperature superconductors; precipitates; Annealing; Critical current density; Equations; Glass; Magnetic fields; Magnetic flux; Magnetic hysteresis; Magnetization; Superconducting magnets; Temperature dependence;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
