Title :
Enhancement of critical currents in bulk and Ag-sheathed Bi(Pb)-2223 superconductors
Author :
Brauer, D.J. ; Eujen, R. ; Hudepohl, J.
Author_Institution :
Anorganische Chem., Bergische Univ. GH, Wuppertal, Germany
fDate :
3/1/1991 12:00:00 AM
Abstract :
The superconducting properties of the Bi(Pb)-2223 phase have been optimized. Prolonged annealing of coarse powder raised the jc in bulk samples to as high as 1100 A-cm-2 at 77 K. The temperature dependence between 96 and 4.2 K was studied, where jc rose gradually from 120 to 2100 A-cm-2. Tc dropped from 107 K to 64 K in magnetic fields up to 4 T, but decreased by only 1 K/T in higher fields. A tape prepared by rolling and subsequent annealing of Ag tubes containing Bi(Pb)2223 powder exhibited a jc of 1700 A-cm-2 at 77 K and 11000 A-cm-2 at 4.2 K. The latter jc dropped to 3000 A-cm-2 in a magnetic field of 0.25 T, but it was still 1200 A-cm-2 in a 10-T field. A tape fabricated by pressing a drawn and annealed wire proved to be less sensitive to low magnetic fields
Keywords :
annealing; bismuth compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; lead compounds; powders; strontium compounds; superconducting transition temperature; 107 to 64 K; 4.2 to 96 K; Ag tubes; Ag-sheathed Bi(Pb)-2223 superconductors; BiPbSrCaCuO; annealing; bulk samples; coarse powder; critical currents; high temperature superconductivity; pressing; rolling; tape; temperature dependence; transition temperature; wire; Annealing; Crystalline materials; High temperature superconductors; Magnetic fields; Magnetic materials; Powders; Pressing; Silver; Superconductivity; Temperature dependence;
Journal_Title :
Magnetics, IEEE Transactions on
