Superconducting Tl-Ca-Ba-Cu-O thin films with zero resistance at temperatures of up to 120 K

Abstract
We have prepared superconducting Tl‐Ca‐Ba‐Cu‐O thin films on a variety of substrates with transition temperatures as high as ≂120 K, confirmed by sharp onsets of substantial Meissner and shielding signals at the same temperatures. The properties of the films are found to depend sensitively on the post‐annealing conditions. Highly textured c‐axis‐oriented films comprised mostly of Tl2Ca1Ba2Cu2Ox, Tl1Ca2Ba2Cu3Ox, and Tl2Ca2Ba2Cu3Ox were synthesized by varying the annealing procedure with corresponding maximum superconducting transition temperatures of ≂100, 110, and 120 K, respectively.