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

The critical current property of Bi2Sr2Ca2Cu3Ox(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 degrees)/J(c)(90 degrees) 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. (c) 2010 Elsevier B.V. All rights reserved.