Articles in 2012

In most unconventional superconductors, the superconducting phase is adjacent to a phase with some type of magnetic order. However, this is not a universal feature. For example, no magnetic order has so far been observed in Sr₂RuO₄. Now, low-energy muon relaxation experiments show the presence of a static magnetic order for this material, suggesting that this feature may in fact be universal.

Mesoporous colloidal gels with solid-like viscoelasticity formed from oil-in-water nanoemulsions are reported. Gelation is thermoreversible and occurs through interdroplet bridging of an end-functionalized oligomer. The gels can be photocrosslinked to encapsulate lipophilic biomolecules for their subsequent release through ultraviolet photolysis.

It is well known that to reduce dissipation in a superconductor it is necessary to introduce artificial pinning centres, that is, small regions in which superconductivity is suppressed. This is usually achieved by introducing small regions of non-superconducting phases. A new concept of pinning centres, the local suppression of superconductivity induced by strain, is now demonstrated.

The realization of ultrastable, nanostructured glassy polymer films by pulsed-laser evaporation is reported. Compared with standard poly(methyl methacrylate) glass, these polymer glasses are 40% less dense and have a 40-degree-higher glass transition temperature. Their unique properties, which are a manifestation of their globular nanostructure, should make these glasses attractive for applications where weight and stability are critical.

Flexible electronics and other nanoscale devices require simple yet reliable assembly procedures. An optical welding technique for metal nanowires, based on surface plasmon resonances, is now used to fabricate interconnected nanowire networks with enhanced electrical properties for use as transparent electrodes in solar cells and other electrical devices.

Mast cells act to enhance immune responses through the release of insoluble granules that contain inflammatory mediators. Now, submicrometre polymer particles are shown to replicate and enhance the functions of mast-cell granules in vivo, such as the targeting of draining lymph nodes and the timed release of encapsulated mediators. The particles can also polarize the resulting immune response.

In the quest for more efficient thermoelectrics, a common strategy has been to introduce nanostructures in bulk crystals, thus reducing the thermal conductivity without affecting the electrical transport properties. A route is now presented in which the aggregation of nanoplatelets creates nanostructured materials that have higher thermoelectric efficiencies than their bulk counterparts.