Preparation and Transport Properties of TlBa2Ca2Cu3Oy Thin Films by Metalorganic Deposition

Thin films of the TlBa2Ca2Cu3O y (Tl-(1223)) system were successfully prepared on SrTiO3(100) substrates by means of the deposition of a Ba-Ca-Cu-O precursor by the metalorganic deposition (MOD) method with the reaction of Tl2O3 vapor. The films (1 µm thickness) were composed entirely 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 current (I c) of 6.3 A with a 1-mm-wide bridge, which corresponds to the transport critical current density (J c) of 6.3×105 A/cm2 at 77 K in a zero magnetic field. When the magnetic field was applied perpendicular to the a-b plane, the J c values were 2.0×104 and 6.0×105 A/cm2 at 77 and 40 K in a 1 T field, respectively. Moreover, the 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 and good intergranular connectivity.