Superconducting epitaxial Tl2Ba2CaCu2O8 films on sapphire with cerium oxide buffer layers

Abstract
Epitaxial Tl2Ba2CaCu2O8 films were prepared on (11̄02)Al2O3 with (100) CeO2 buffer layers. The Tl2Ba2CaCu2O8 was epitaxially oriented with its c axis perpendicular to the substrate surface and [100] Tl2Ba2CaCu2O8 aligned with [100] CeO2 and [22̄01] Al2O3. The films exhibited Tc of 97–98 K as measured both inductively and by ac magnetic susceptibility. Direct transport critical current density Jc at 75 K was 2.8×105 A/cm2.