Effect of number of filaments on the critical current density in multifilamentary Bi-2223 tape

Abstract The critical current property of Bi 2 Sr 2 Ca 2 Cu 3 O x (Bi-2223) silver-sheathed tape has been remarkably improved by application of ConTrolled Over Pressure (CT-OP) process with adjusting temperature and oxygen partial pressure. For further improvement of the property of Bi-2223 tapes, the effect of number of filaments on the critical current density J c was investigated. It was found that J c was higher and its decrease with increasing magnetic field was weaker in the tape with larger number of filaments. In addition, the irreversibility field B i increased with increasing filament number. The field-angle anisotropy J c (0°)/ J c (90°) of the tape with the largest filament number was smallest, where the field-angle was measured from the a – b plane. However, the out-of-plane misorientation angle is fairly small in this tape. Hence, the low field-angle anisotropy in this tape seems to be attributed to improved superconductivity in the block layers in the superconducting region near the interface with silver matrix.