Angular Dependence of Critical Current in Ag-Seathed Bi(2223) Superconductor Tape

The critical current Ic (B.T.θ) of Ag-sheathed Bi(2223) tape was measured at 4.2 and 77 K in magnetic field up to 6 T as a function of the field direction. The maximumIc is observed when the flux line are along the CuO2 planes. This effect is due to an intrinsic pinning between CuO2 layers. When H > 0.5 T at 4.2 K. Ic decreases very slowly with the magnetic field. The results are consistent with our early-proposed scaling laws for flux pinning in Ag-sheathed tape.