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.