Precursor Delivery for the Deposition of Superconducting Oxides: a Comparison Between Solid Sources and Aerosol

Epitaxial thin layers of YBa 2Cu 3O7−x (Tc=90 K, Jc (OT, 77 K) = 2 106 A cm-2) were synthesised by thermal decomposition (750 − 830 °C) of tetramethylheptanedionates of yttrium, barium and copper in the presence of oxygen. Three different precursor delivery systems have been used: In the first, the precursor's surface is flushed with the carrier gas (Ar), in the second, argon is directly injected through the powder leading to a much higher transport rate, and in the third, a liquid (diketonates in a solvent) is nebulized via a piezoelectric transducer. The transport and deposition rates obtained in these three different reactors will be compared.