Chapter 1.4: Electro-Magnetic Properties of Bi-2223 Wires

The electromagnetic properties such as critical current density and irreversibility field are described for superconducting Bi-2223 wires fabricated by the controlled over-pressure (CT-OP) process. The improvement of the critical current density was more significant in the magnetic field parallel to the tape surface than in the normal field. This improvement is limited in the low magnetic field region and the irreversibility field was not improved by this process. The observed properties are analyzed using the theoretical model of flux creep and flow. It is found that the improvement of the properties by introducing the CT-OP process is mainly ascribed to the improvement of the crystal alignment by the high pressure, while the pinning mechanism is unchanged.