The bulk samples with the composition Bi1.8Pb0.4Sr1.9Ca2.1 Cu3.5Oy + x wt.% MgO (x = 0, 0.5, 2, 5, 10 and 15) were prepared by sintering at 840°C for 240 h after partial-melting at 875°C for 1 h. The sample with 0.5 wt.% MgO addition shows the lowest melting temperature of Bi-2212 phase and the highest conversion of Bi-2212 phase to Bi-2223 phase. With increasing MgO content, the width of hysteresis loop ΔM of the bulk samples at 77 K increases (0 ≤ x ≤ 5), and then decreases (5 ≤ x ≤ 15). The largest ΔM appears in the sample with 5 wt.% MgO addition. It is suggested that an amount (∼5 wt.%) of MgO addition in the (Bi, Pb)-2223 superconductors can increase Jc due to improving the flux pinning. In contrast, MgO overdoping (≥5 wt.%) decreases Jc due to decreasing the conversion of Bi-2212 phase to Bi-2223 phase.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering