Synthesis of YBa<SUB>2</SUB>Cu<SUB>4</SUB>O<SUB>8</SUB> in air through complex precursor formation and fine-particle techniques

We report the successful synthesis in air of the superconductor YBa<SUB>2</SUB>Cu<SUB>4</SUB>O<SUB>8</SUB> (1-2-4) without the need of high oxygen pressure or an alkali-carbonate based catalyst. The technique involves formation, in solution, of a fine-particle-complex based precursor. The 1-2-4 phase then forms in air with a single firing of 30 min at 900&#176;C and a T<SUB>c</SUB> near 80 K. We also report some results of attempts to prepare 1-2-4 using precursors from sol-gel and spray drying