Highly oriented Tl\u3csub\u3e2\u3c/sub\u3eBa\u3csub\u3e2\u3c/sub\u3eCa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e10\u3c/sub\u3e thin films by pulsed laser evaporation

Abstract

We have fabricated superconducting thin films on MgO(100) substrates with nearly pure Tl2Ba2Ca2Cu3O10 (2:2:2:3) phase using pulsed laser evaporation and post-annealing. The films had c axes perpendicular to the substrates. Superconducting films with onset temperatures of 125 K and zero resistance at 110 K were obtained. X-ray microprobe fluorescence measurements indicate that a typical composition of films is Tl0.66Ba1.77Ca1.46Cu3Oχ, which is low in Tl compared to that expected for the 2:2:2:3 phase. A typical grain size is greater than 10 µm as revealed by scanning electron microscopy