Fabrication of Tl-Ba-Ca-Cu-O films by annealing rf-sputtered Ba-Ca-Cu-O films in thallium oxide vapors

Abstract
Thin, superconducting Tl‐Ba‐Ca‐Cu‐O films were grown using a two‐step fabrication process which involved the growth of Ba‐Ca‐Cu‐O films by reactive magnetron sputtering followed by ex situ high‐temperature crystallization and thallination under thallium oxide vapors. Films were thallinated with both Tl2O3 and Tl2Ba2CuO6 as the source for thallium oxide vapors. Highly oriented films were obtained with the c axis perpendicular to the surface of the film. Best films had a Tc (R=0) of 104 K and a critical current density of 5×104 A/cm2 at 77 K.