Jc enhancement in Tl2Ba2CaCu 2Ox thin films by introduction of CeO2 nanodots on substrates

摘要

Tl2Ba2CaCu2Ox (Tl-2212) thin films with enhanced transport critical current densities Jc were fabricated by using conventional dc sputtering and a post-annealing process. In order to employ artificial defects to improve the flux pinning strength, nano-sized CeO2 dots were deposited on the LaAlO3(001) substrates by radiofrequency (rf) magnetron sputtering from a cerium metal target prior to the growth of Tl-2212 films. The critical current density J c (77K) of the Tl-2212 thin film on the nanodot-introduced substrate reaches 6 × 106Acm- 2 at self-field, which is 1.7 times larger than that on the normal substrate. The enhancement of the J c in Tl-2212 film grown on the substrate with artificial defects is more obvious in magnetic fields. At 0.5T dc magnetic field, a Jc (77K) of 3.5 × 104Acm- 2 is observed, which is about 13 times larger than that on the normal substrate.