A new hybrid two-zone/crucible furnace process for the growth of epitaxial Tl₂Ba₂CaCu₂O₈ superconducting films

Epitaxial Tl2Ba2CaCu2O8 (Tl-2212) films similar to 5500 Angstrom thick are grown on LaAlO3(100) substrates using a new hybrid two-zone/crucible furnace process enabling precise control of thallination. This method combines the best features of both conventional crucible and two-zone processing for the first time: superb film properties and reduced handling of hazardous Tl-oxide powders. Single-phase, highly c-axis oriented Tl-2212 films are grown with smooth morphology, Meissner transition similar to 103 K, and critical current density similar to 1.1 x 10(7) A/cm(2) at 5 K for twenty consecutive runs without having to change or add to the Tl-oxide source.