Preparation of a Ag-doped Bi-Sr-Ca-Cu-O bulk sample by the floating-zone method

Bulk samples with nominal composition of Bi 2 Sr 2 CaCu 2 O y doped with 0, 10 and 20 weight % Ag were prepared by the floating-zone method at growth rates of 2 mm/h and 5 mm/h. Ag-doping seems to slightly enhance J c , while annealing is very effective for J c enhancement. From preliminary ac susceptibility measurements, the J c enhancement by annealing is considered to be due to improvement of the weak link between superconducting grains. The 10% Ag-doped sample grown at 2 mm/h possessed J c of 5360 A/cm 2 at 77 K under zero magnetic field after annealing.