Critical current measurements of DI-BSCCO tapes as a function of angle in high magnetic fields

Controlled Over-Pressure is used by Sumitomo Electric Industries Ltd. to process so-called DI-BSCCO Bi-2223 superconducting tape reaching high critical current (IC) in high magnetic fields. This paper reports the critical current of DI-BSCCO tape at 77 K in low fields and at 4.2 K in our horizontal split-pair magnet in fields up to 13 T at various angles between the surface of the tape and the direction of the magnetic field. These critical current data are strongly influenced by the anisotropy of Bi-2223, the texturing of the tape and the magnetic history of the magnetic field. The magnetic field and angular dependence of IC at 77 K can be parameterised with a simple anisotropic Kim model. For 4.2 K measurements where large currents and magnetic fields are required, it is demonstrated that a split-current-lead design can be used to reduce rotation of the probe during the IC measurements.