PREPARATION AND TRANSPORT-PROPERTIES OF TLBA2CA2CU3OY THIN-FILMS BY METALORGANIC DEPOSITION

Thin films of the TlBa2Ca2Cu3Oy (Tl-(1223)) system were successfully p repared on SrTiO3(100) substrates by means of the deposition of a Ba-C a-Cu-0 precursor by the metalorganic deposition (MOD) method with the reaction of Tl2O3 vapor. The films (1 mum thickness) were composed ent irely of the (1223) phase and had a highly c-axis-oriented structure. The films had T(c zero) = 106 K and showed a high transport critical c urrent (I(c)) of 6.3 A with a 1-mm-wide bridge, which corresponds to t he transport critical current density (J(c)) of 6.3 X 10(5) A/cm2 at 7 7 K in a zero magnetic field. When the magnetic field was applied perp endicular to the a-b plane, the J(c) values were 2.0 X 10(4) and 6.0 X 10(5) A/CM2 at 77 and 40 K in a 1 T field, respectively. Moreover, th e history effect of J(c) in the magnetic field was not observed at 77 K below 0.1 T. These results indicate that the Tl-(1223) film, formed by the MOD method, has strong magnetic flux pinning characteristics an d good intergranular connectivity.