Superconducting bulks can be magnetized to act as powerful permanent magnets; however, for high trapped fields at temperatures below 77 K, bulks have poor thermal stability and are limited by low mechanical strength. The trapped fields reported in this paper are between two stacks of commercial high-temperature superconducting tape each with 120 layers, magnetized by field cooling. 7.34 T was trapped at approximately 4.2 K, the highest field ever achieved for such a sample. The trapped field also continued to increase below 20 K showing high thermal stability, largely due to the silver over-layer which effectively dissipates heat.

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⁻¹YBCO 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 μm wide tracks.

In this paper, we present an inkjet printing approach suited for the deposition of photocatalytically active, transparent titanium oxide coatings from an aqueous, colloidal suspension. We used a bottom-up approach in which a microwave-assisted hydrothermal treatment of titanium propoxide aqueous solutions in the presence of ethylenediaminetetraacetic acid and triethanolamine was used to create suspensions containing titania nanoparticles. Different inkjet printing set-ups, electromagnetic and piezoelectric driven, were tested to deposit the inks on glass substrates. The presence of preformed titania nanoparticles was expected to make it possible to reduce the heating temperature necessary to obtain the functionality of photocatalysis which can widen the application range of the approach to heat-sensitive substrates. We investigated the crystallinity and size of the obtained nanoparticles by electron microscopy and dynamic light scattering. The rheological properties of the suspensions were evaluated against the relevant criteria for inkjet printing and the jettability was analyzed. The photocatalytic activity of the obtained layers was analyzed by following the decomposition of a methylene blue solution under UV illumination. The influence of the heat treatment temperature on the film roughness, thickness and photocatalytic activity was studied. Good photocatalytic performance was achieved for heat treatments at temperatures as low as 150 degrees C, introducing the possibility of using this approach for heat-sensitive substrates.