The Microstructure and Superconducting Properties of Bi,Pb-2223 Thin Film Fabricated by RF Sputtering and Annealing Method

We investigated the microstructures and superconducting properties of Bi,Pb-2223 thin films on SrTiO₃(100) fabricated by radio-frequency (RF) sputtering and annealing. Most as-deposited films fabricated by RF sputtering did not exhibit a superconducting transition due to their low crystallinity, their deviation from the composition of Bi-2223, and their low intergrain connectivity. The as-deposited films did not contain Pb. To obtain the Bi,Pb-2223 phase, we annealed the film with Bi,Pb-2223 pellets and powder. After annealing, we confirmed that the thin film contained Pb. T_c^zero = 100 K was obtained in Bi,Pb-2223 thin film after post-annealing. We observed strong 00l peaks and a sharp quadrupole in X-ray θ - 2θ and φ-scan measurements. These results suggest that this film consists of a single phase of Bi,Pb-2223 and has a biaxial orientation. The Bi,Pb-2223 thin film had a maximum J_c of 0.1 × 10⁵ A/cm² at 78 K in a magnetic field of 2 T. Furthermore, Bi,Pb-2223 exhibited very strong anisotropy in its J_c-B angle characteristics.