Electrodeposition of biaxially aligned Tl-based superconductors on Ag tapes

An alternative preparation method of Tl(1212) and Tl(1223) biaxially aligned tapes on Ag was developed: electrodeposition. This method is based on the co-deposition of the metals by an electrochemical process followed by a high temperature heat treatment in order to form the superconducting phase. Nitrates of the metals are dissolved in DMSO and the deposition on conducting substrates is performed in a standard three electrodes cell. The thermal treatment is performed in a high isostatic pressure furnace (1 bar O₂/50 bar He) in order to prevent Tl evaporation. The main advantage of this low cost technique is that it is very fast, (~1 μm/min) and can be easily scaled up to produce long length tapes in a continuous process. The desired stoichiometry is obtained by varying iteratively the concentration of nitrates in the starting solution. Moreover, the reaction temperature and time of the thermal treatment are drastically reduced with respect to the powder synthesis due to the amorphous form of the precursor. Excellent biaxial alignment is observed on both {110} Ag single crystal and textured Ag tapes, while epitaxial growth is observed on SrTiO₃ single crystal. T_c of 118 K and 60 K were measured resistively for Tl(1223) and Tl(1212) samples, respectively