OPTIMIZATION OF GROWTH OF EPITAXIAL TL2BA2CA1CU2O8 SUPERCONDUCTING THIN-FILMS FOR ELECTRONIC DEVICE APPLICATIONS

Epitaxial thin films of Tl2Ba2Ca1Cu2O8 (Tl-2212) superconductor have b een grown on single crystal (100) lanthanum aluminate (LaAlO3) substra tes by a two stage process: laser ablation of a Ba-Ca-Cu-O (0212) sint ered target and post-deposition anneal ex-situ in a thallium environme nt. The films are c-axis oriented with in-plane epitaxy as determined by x-ray diffraction (XRD theta-2 theta and phi-scans). Superconductin g transition temperatures as high as 105.5K have been obtained both fr om four-probe resistance and a.c. magnetic susceptibility measurements . Film morphology and chemical composition have been assessed by scann ing electron microscopy (SEM) and energy dispersive x-ray analysis (ED X). Sensitivity of the precursor film to environmental exposure has pr oven to be a determining factor in the reproducibility of film growth characteristics. The effect of oxygen partial pressure and substrate t emperature used in the precursor film synthesis, as well as the thalli um annealing temperature and duration, on the growth of Tl-2212 thin f ilms is reported.