Growth of Tl-2212 Films on CeO2-Buffered Sapphire Substrates

Tl2Ba2CaCu2O8 (Tl-2212) films were prepared on r-cut sapphire substrates buffered with CeO2 by dc magnetron sputtering and post-annealing method. The in situ two-temperature process was used to grow CeO2 buffer layers. XRD and AFM measurements showed that CeO2 films deposited at temperature of 370-470°C were excellent c-axis orientation and had smooth surface. SEM observations demonstrated that the Tl-2212 films’ surface morphology was changed from condensing crystal structure to plate-like structure when the CeO2 deposition temperature was increased. The best Tl-2212 film’s critical temperature Tc can reach to 108.3 K, and critical current density Jc obtained at 5.33 MA/cm2 (77 K, 0 T).