Influences of Thalliation on the Morphology and Critical Temperature of Tl₂Ba₂CaCu₂O₈ Thin Films

Tl₂Ba₂CaCu₂O_x (Tl-2212) thin films were prepared by the two-step technique. A precursor film was first prepared by the pulsed laser deposition method, and then experienced the incorporation of thalliation in a one-step or two-step annealing process. The experimental results show that the two-step annealing process produces dense and smooth films, and that the one-step annealing process produced a high critical temperature film of 101K, but the transition width is wide. Precursor films with homogeneous Ba₂Ca_1.3Cu_2.1O_x composition are essential for producing high quality Tl-2212 films.