Thin films of Bi-2223 fabricated on SrTiO3(100) substrates by dc sputtering were found to have a transition temperature (Tc) as low as that of bulk-phase Bi-2223. Subsequent annealing of these precursor films in the presence of Bi,Pb-2223 pellets increased this Tc value from 72 to 105 K, making it comparable to bulk-phase Bi,Pb-2223. Strong (00l) peaks and a sharp quadrupole were observed in this annealed film, indicating a main phase of Bi,Pb-2223 with a c-axis orientation by the X-ray diffractometry (XRD) measurements. A maximum critical current density (Jc) of 3.3 × 105 A/cm2 at 77 K was also obtained with the Bi,Pb-2223 thin film, which is a value that is much higher than that of commercial Bi,Pb-2223 tapes. Jc values of thin films were strongly dependent on the annealing temperatures between 854 °C and 866 °C. In this temperature range, XRD data show that the thin films were not a single phase of Bi,Pb-2223, suggesting only a slight interruption of the supercurrent. Although, the films have a good c-axis and ab-axis alignments. Thus, although the films were not perfect, the improvement in microstructure allows for a much higher Jc value.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering