The Influence of $\hbox{CeO}_{2}$ Nano-Dots Decoration on Substrates on Flux Pinning Strength in $\hbox{Tl}_{2} \hbox{Ba}_{2}\hbox{CaCu}_{2}\hbox{O}_{8}$ Thin Films

Nano-sized
$\hbox{CeO}_{2}$
dots were deposited on (001)
$\hbox{LaAlO}_{3}$
substrate by rf magnetron sputtering. After the processing of the artificial decoration defects on the substrate, 100-nm, 150-nm, 200-nm, and 400-nm-thick
$\hbox{Tl}_{2}\hbox{Ba}_{2}\hbox{CaCu}_{2}\hbox{O}_{8}$
(Tl-2212) thin films were grown on it, using dc magnetron sputtering and post annealing process. AFM images showed that the
$\hbox{CeO}_{2}$
nano-dots were distributed well on the substrate surface with 70 nm in diameter and 5 nm in height, and the density of nano-dots was
$25\pm 3\ \hbox{dots}/\mu\hbox{m}^{2}$
. SEM images were used to observe the variations on film surface. Transport critical current density
$J_{c}$
was measured both on Tl-2212 film with nano-dots decorated substrate and untreated single crystal
$\hbox{LaAlO}_{3}$
substrate. From the results,
$J_{c}$
values of Tl-2212 films with nano-dots decorated substrate were lifted significantly, and the pinning strength was improved on Tl-2212 films by nanostructure defects induced from nano-dots.