Sputtered Tl-Ca-Ba-Cu-O Thin Films with Zero Resistivity at 98 K

Abstract
Superconducting Tl-Ca-Ba-Cu-O thin films were prepared by rf magnetron sputtering from a sintered Tl3Ca2Ba2Cu3O x target. After post-annealing, films grown on (100) MgO substrates exhibited the best superconducting properties with an onset temperature as high as 110 K and zero resistivity at 98 K. No resistive tails were observed at measuring current densities of 0.5–5 A/cm2. X-ray diffraction patterns indicated that the major phase of the films is Tl2Ca1Ba2Cu2O x .