Screen-printing of ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides

The feasibility of screen-printing process of hard ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides (CCSO) is investigated. In CCSO, the exothermic oxidation of carbon generates a smolder thermal reaction wave that propagates through the solid reactant mixture converting it to the desired oxides. The complete conversion of hexaferrites occurs using reactant mixtures containing 11 wt. % of carbon. The BaFe12O19 and SrFe12O19 hexaferrites had hard magnetic properties with coercivity of 3 and 4.5 kOe, respectively. It was shown that the synthesized nanoparticles could be used to fabricate permanent magnet structures by consolidating them using screen-printing techniques

Origin of the Superconductivity in the Y-Sr-Ru-O and Y-Sr-Cu-O Systems

We report on the structural, magnetic, and Raman-scattering studies of double perovskite structure Sr2Y(Ru1-xCux)O6-d systems made by systematic synthesis processes with various numbers of doping concentrations and sintering temperatures. We observed different behaviors resulting from the different thermal treatments. In particular, superconductivity in Cu-doped Sr2YRuO6 has been observed only for partially melted ceramic materials. We show that superconductivity is associated with the 1:2:3 phase (YSr2Cu3Ot), similar to that of Y-Sr-Cu-O samples sintered at high temperature

Roadmap on printable electronic materials for next-generation sensors

The dissemination of sensors is key to realizing a sustainable, ‘intelligent’ world, where everyday objects and environments are equipped with sensing capabilities to advance the sustainability and quality of our lives—e.g., via smart homes, smart cities, smart healthcare, smart logistics, Industry 4.0, and precision agriculture. The realization of the full potential of these applications critically depends on the availability of easy-to-make, low-cost sensor technologies. Sensors based on printable electronic materials offer the ideal platform: they can be fabricated through simple methods (e.g., printing and coating) and are compatible with high-throughput roll-to-roll processing. Moreover, printable electronic materials often allow the fabrication of sensors on flexible/stretchable/biodegradable substrates, thereby enabling the deployment of sensors in unconventional settings. Fulfilling the promise of printable electronic materials for sensing will require materials and device innovations to enhance their ability to transduce external stimuli—light, ionizing radiation, pressure, strain, force, temperature, gas, vapours, humidity, and other chemical and biological analytes. This Roadmap brings together the viewpoints of experts in various printable sensing materials—and devices thereof—to provide insights into the status and outlook of the field. Alongside recent materials and device innovations, the roadmap discusses the key outstanding challenges pertaining to each printable sensing technology. Finally, the Roadmap points to promising directions to overcome these challenges and thus enable ubiquitous sensing for a sustainable, ‘intelligent’ world

Progress in scale-up of REEBCO STAR™ wire for canted cosine theta coils and future strategies with enhanced flexibility

We report recent developments in the scale-up of symmetric RE-Ba-Cu-O (R$E$BCO) tapes with 15–22 μm thick substrates. Using these symmetric R$E$BCO tapes, we fabricated up to 10 m long, symmetric tape round (STAR™) R$E$BCO wires, less than 2 mm diameter, using 1.02 mm and 0.81 mm diameter copper formers. The critical current of the long STAR™ wires made in lengths of 2–10 m ranges from 465 A to 564 A at 77 K, self-field. This wire was then used to construct a single-layer, full-depth groove, three-turn canted cosine theta (CCT) coil with a minimum bend radius of 15 mm. This three-turn CCT coil retains 95% of its $I_{c}$ even when wound at a such a small bend radius. This result confirms the capability of fabricating CCT coils with STAR™ wire at a tilt angle of 30º which would yield a dipole transfer function of 0.48 T kA$^{−1}$ at a 15 mm bend radius. Further, the architecture of STAR™ wire was modified for an $I_{c}$ retention of >90% at an even smaller bend radius of 10 mm with the aim of increasing the dipole transfer function. The higher dipole transfer function enabled by STAR™ wire is an important step toward the eventual goal of a 5 T maximum dipole field in a R$E$BCO-based CCT coil. At a bend radius of 10 mm, a six-layer STAR™ wire exhibits a critical current of 288 A at 77 K, self-field, i.e. 94% $I_{c}$ retention and 617 A at 4.2 K in a 15 T background field, which equals a $J_{e}$ of 412.7 A mm$^{−2}$ at a Lorentz force of 9.3 kN m$^{−1}$. This level of flexibility and the high performance of STAR™ wire in high fields at 4.2 K and with a small bend radius underscores its potential use in compact and low-cost high-field magnet and related applications