Mp. Siegal et al., Remarkable properties of Tl-Ba-Ca-Cu-O thin films following post-growth high-temperature annealing, IEEE APPL S, 9(2), 1999, pp. 1555-1558
Tl-2212 and Tl-1212 are the two easiest unsubstituted Tl-Ba-Ca-Cu-O superco
nducting thin films to grow, Both phases exhibit T-c greater than or equal
to 95 K, J(c)(5K) > 10 MA/cm(2) and smooth morphologies, We report on the p
roperties of both materials following one hour furnace anneals in dry ambie
nts of pure oxygen or nitrogen at temperatures ranging from 50 - 700 degree
s C, The stability of these films to high temperatures in each ambient is i
mportant for device processing. Of equal interest is the controlled partial
volatilization of Tl-oxide at modest temperatures from nano-size regions w
ithin Tl-1212 films. We correlate such modifications with increases in flux
pinning strength in Tl-1212 films. Tl-2212 films maintain their supercondu
cting properties to even higher temperatures than Tl-1212 films. Optimum an
nealing appears to also increase flux pinning, although not to the same deg
ree as for Tl-1212 films.