Pulsed Laser Evaporation of Tl-Ba-Ca-Cu-O Films

Pulsed Laser Evaporation (PLE) has been shown to produce superconducting films of excellent quality. We will be discussing the results obtained from the PLE of Tl-Ba-Ca-Cu-O using a frequency doubled Nd:YAG laser operating at 532 mn. Films were deposited on SrTiO3, MgO, yttrium stabilized ZrO2, and polycrystalline Al2O3. Nearly single phase films of Tl2Ba2Ca2Cu3O10 on MgO were routinely obtained. The best films exhibited a superconducting transition onset temperature of about 125K and zero resistance at 110K. The films had a c-axis orientation perpendicular to the substrates. X-ray microprobe fluorescence measurements indicate that a typical composition of the films is Tl0.66Ba1.77Ca1.46Cu3Ox, which is low in Ti compared to that expected for the 2:2:2:3 phase. The typical grain size is greater than 10 μm as revealed by scanning electron microscopy.