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.