Properties of TI-1223 Superconducting Thick Films Fabricated From Precursor Inks Using A Thallium Vapor Transport Process

Using a two-zone thallium vapor transport furnace and a thick film ink process, we have successfully made superconducting films 10 to 50 µm thick on a variety of substrates. Ba2Ca2Cu3Ox and Bi0.22Sr1.6Ba0.4Ca2Cu3Ox precursor films with and without Ag additions were made by mixing powders in an organic vehicle, painting a substrate and burning the vehicle off. Films were converted to the superconducting phase by passing an O2 carrier gas over a TI2O3 source and then the sample. TBCCO 1223 films generally form over a narrow sample temperature range near 860°C, whereas TBSBCCO films form 1212, 1223 or a mixture of these phases depending on sample annealing temperature and O2 partial pressure. TBCCO Tc's average 104K with zero-field JC(77K)≈3500 A/cm2’ while TBSBCCO Tc's are higher at 110K with Jc=6800 A/cm2. Both compounds show weak-link behavior in a magnetic field.