Preparation and characterization of Tl2Ba2Ca2Cu3Ox superconducting thin films

Superconducting Tl-Ba-Ca-Cu-O thin films have been fabricated by laser ablation. There are two steps in this process. First, an excimer laser is focused onto the Ba-Ca-Cu-O target forming a Ba-Ca-Cu-O plume. These particles are then deposited on substrate; second, the precursor films are placed into quartz tube to anneal in the presence of unfired Tl2Ba2Ca2Cu3O10 pellet to form the superconducting phase. Zero-resistance temperature Tc and critical current density Jc of the best film were 12 Ik and 1 X 106A/cm2 (at 77 K) respectively. X-ray diffraction (XRD) and secondary electron microscope (SEM) have been used to study the crystalline structure, while the composition are analyzed by high energy ion backscattering and checked with energy dispersion X-ray analysis (EDAX) and secondary ion mass spectroscopy (SIMS). Results show that these superconducting films are predominately composed of the (2223) phase and highly oriented. A platelet structure plays an important role on the quality of film.