METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION OPEN FLOW THALLIUM ANNEALING ROUTE TO EPITAXIAL TL2BA2CA2CU3O10 THIN-FILMS

Phase-pure epitaxial Tl2Ba2Ca2Cu3O10 thin films have been grown on sin gle crystal (110) LaAlO3 substrates using an improved metal-organic ch emical vapor deposition process. First, Ba-Ca-Cu-O(x) precursor films are grown on LaAlO3 (110) substrates using Ba(hfa)2.tet, Ca(hfa)2.tet, and Cu(hfa)2 (hfa=hexafluoroacetylacetonate; tet=tetraglyme) as volat ile metalorganic precursors. Thallium is then incorporated into the fi lms during a post-anneal in the presence of a Tl2O3, BaO, CaO, CuO pow der mixture at 820-degrees-C for 12 h in a flowing 10% O2/Ar atmospher e. The films have a transport-measured T(c)=115 K and J(c)=1.5x10(5) A /cm2 (80 K), while magnetic hysteresis measurements yield J(c)=6X10(5) A/cm2 (77 K). Preliminary surface resistance measurements give R(s)=0 .35 mOMEGA at 5 K, 10 GHz.