Superconducting Tl2Ba2CaCu2O8 thin films prepared by post-annealing in a flow-through multiple-zone furnace

摘要

Tl(sub 2)Ba(sub 2)CaCu(sub 2)O(sub 8) thin films were prepared for the first time by use of a multiple-zone flow-through thallination process. Thallous oxide was volatilized from condensed thallium oxide in a low temperature source zone and convectively transported to a higher temperature thallination zone in which initially amorphous Ba(sub 2)CaCu(sub 2)O(sub 5) precursor films were located. By careful control of the source temperature, film temperature, flow rate, anneal time, and rates of heat up and cool down, smooth Tl(sub 2)Ba(sub 2)CaCu(sub 2)O(sub 8) thin films were prepared on (100) LaAlO(sub 3) with the following properties: inductive (Tc) of 107.6 K and 80% transition width of 1.3 K, transport J(sub c) at 75 K of 1.3 (times) 10(sup 5) A/cm(sup 2), and R(sub s) at 10 GHz and 80 K of 1.3 m(Omega). The scalability of the process to large area film processing was demonstrated by the preparation of Tl(sub 2)Ba(sub 2)CaCu(sub 2)O(sub 8) thin films on LaAlO(sub 3) three-inch diameter wafers.