title: Submicrometer Superconducting YBa2Cu3O6+x Particles Made by a Low-Temperature Synthetic Route.
abstract: Evidence suggests that superconducting, orthorhombic YBa(2)Cu(3)O(6+x)+ (x greater, similar 0.5) is always produced by oxidation of the oxygen-deficient, tetragonal form (x less, similar 0.5) of this phase (commonly referred to as 123). A synthetic route whereby solution-derived, carbon-free precursors are decomposed at 650 degrees to 700 degrees C in inert atmosphere to yield tetragonal 123 is now available. Appropriate precursors include hydrated oxides derived from the hydrolysis of organometallic solutions and aqueous solution-derived hyponitrites. Subsequent oxidation of the tetragonal phase at 400 degrees C results in submicrometer particles of orthorhombic 123. Superconductivity (T(c) onset approximately 87 K) has been confirmed in these materials by both Meissner effect and specific-heat measurements.
authors.forename: H S
authors.initials: HS
authors.lastname: Horowitz
authors.forename: S J
authors.initials: SJ
authors.lastname: McLain
authors.forename: A W
authors.initials: AW
authors.lastname: Sleight
authors.forename: J D
authors.initials: JD
authors.lastname: Druliner
authors.forename: P L
authors.initials: PL
authors.lastname: Gai
authors.forename: M J
authors.initials: MJ
authors.lastname: Vankavelaar
authors.forename: J L
authors.initials: JL
authors.lastname: Wagner
authors.forename: B D
authors.initials: BD
authors.lastname: Biggs
authors.forename: S J
authors.initials: SJ
authors.lastname: Poon