Ink-jet printing of YBa2Cu3O7 superconducting coatings and patterns from aqueous solutions

The objective of this paper is the development of ink-jet processing as a new technique for chemical solution deposition of YBCO coatings and patterns. Our research is mainly focused on the investigation and determination of the rheological parameters towards the printability of water-based inks in order to produce continuous YBCO coatings or multi-filamentary patterns on SrTiO3 substrates. A 0.185 mol L-1 YBCO ink with a viscosity of 4.77 mPa s and a surface tension of 67.9 mN m (1), resulting in a ratio Re/We(1/2) of 7.37, is developed. Its printing behaviour is further verified using a camera with strobed illumination to quantify the droplet velocity and volume. After optimization of the deposition parameters, a 350 nm thick YBCO coating showing preferential c-axis orientation could be grown on SrTiO3. This layer exhibits a critical current of 0.67 MA cm(-2) at 77 K in self-field. Finally, the shape and dimensions of printed YBCO tracks were determined using optical microscopy and non-contact profilometry, showing 200 nm thick and 200 mu m wide tracks.