Buffer layer/film interactions in the growth of Tl2Ba2Ca1Cu2Ox films on CeO2 buffered sapphire

Tl2Ba2Ca1Cu2Ox thin films have been grown on highly textured CeO2 layers deposited onto R-plane sapphire substrates. The Tl2Ba2Ca1Cu2Ox films have critical temperature (Tc) values around 95 K and current density (Jc) values up to 8×104 A/cm2. The films are c-axis oriented even though we have identified the formation of a polycrystalline BaCe(Tl)O3 layer by reaction between the buffer layer and the superconducting precursor during the thalliation process.