Nanometer Cerium: A Significant Improvement Over Platinum in Bulk YBCO Superconductor

Large grain YBCO superconductors, containing the same atomic percentage of Ce, and that of Pt, were produced via the melt-texturing process. Samples doped with nanometer cerium oxide exhibits an approximate 30% increase in trapped magnetic flux density, relative to submicrometer platinum doped YBCO. A 30% increase in trapped magnetic flux density represents ~ 80% increase in critical current density. Microstructure studies indicate that just like Pt, Ce refines Y211 particles to increase trapped magnetic flux density and critical current density. Cerium is much cheaper than platinum and is therefore, a desirable alternative to Pt in the large-scale production of bulk YBCO superconductors. Another interesting result of this experiment is that the trapped magnetic flux density of Ce-doped samples is unchanging over a large range of melting temperatures used for melt-texturing. In addition to refined Y211, Ce-rich deposits are also formed. The Ce-rich particles are insufficient in number to act as effective pinning centers.