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Increasing theTcof YBa2Cu4O8to 90 K by Sr substitution via the KOH flux method

“…This T c value is obviously higher than the previously reported T c of Sr-substituted Y124 and at the same level of Y124 with doped with 10 at% Ca that substitutes the Y site. [7][8][9][10]22,28,29) In the high-Sr-content region of x = 0.3-0.5, T c remains steady at a high value of 89 K. This remarkable T c increase indicates that Sr substitution strongly affects the electric state of crystalline Y124. The pristine Y124 phase with no Sr substitution shows a c-lattice parameter of 27.23 Å, which is the typical value of pure Y124 synthesized using conventional high-temperature, high-pressure methods, as shown in Fig.…”

“…5) The T c of the Y124 phase is also increased to 90 K by substituting Ca into Y sites. [7][8][9][10] This T c increase is attributed to the hole carrier doping created by replacing Y 3+ with Ca 2+ . In addition, Karpinski et al reported that partially substituting Ba with Sr in the Y124 crystal slightly increased T c .…”

Reacting Oxide Nanoparticles with a Substrate

“…Solid-state reactions are frequently encountered in ceramic processing. Titanate electronic ceramics [1] and oxide superconductors [2] are among the many materials synthesized via solidstate reaction. Solid-state reactions may also occur as an unwanted side effect of high-temperature operation of ceramic-containing devices, e.g.…”