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 Tl 3 Ca 2 Ba 2 Cu 3 O 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/cm 2 . X-ray diffraction patterns indicated that the major phase of the films is Tl 2 Ca 1 Ba 2 Cu 2 O x .