Defect ferromagnetism induced by lower valence cation doping: Li-doped SnO nanoparticles.

To explore the role of Li in establishing room-temperature ferromagnetism in SnO, the structural, electronic and magnetic properties of Li-doped SnO compounds were studied for different size regimes, from nanoparticles to bulk crystals. Li-doped nanoparticles show ferromagnetic ordering plus a paramagnetic contribution for particle sizes in the range of 16-51 nm, while pure SnO and Li-doped compounds below and above this particular size range are diamagnetic. The magnetic moment is larger for compositions where the Li substitutes for Sn than for compositions where Li prevalently occupies interstitial sites.

Defect ferromagnetism in SnO:Zn hierarchical nanostructures: correlation between structural, electronic and magnetic properties.

We report on the ferromagnetism of Sn Zn O ( ≤ 0.1) hierarchical nanostructures with various morphologies synthesized by a solvothermal route. A room temperature ferromagnetic and paramagnetic response was observed for all compositions, with a maximum in ferromagnetism for = 0.

A Remarkable Multitasking Double Spiropyran: Bidirectional Visible-Light Switching of Polymer-Coated Surfaces with Dual Redox and Proton Gating.

Smart or functional surfaces that exhibit complex multimodal responsivity, e.g., to light, heat, pH, etc.

Light Emission as a Probe of Energy Losses in Molecular Junctions.

Visible light emission was observed for molecular junctions containing 5-19 nm thick layers of aromatic molecules between carbon contacts and correlated with their current-voltage behaviors. Their emission was compared to that from Al/AlOx/Au tunnel junctions, which has been previously attributed to transport of carriers across the AlOx layer to yield "hot carriers" which emit light as they relax within the Au contact. The maximum emitted photon energy is equal to the applied bias for the case of coherent tunneling, and such behavior was observed for light emission from AlOx and thin (<5 nm) molecular junctions.

Preparation and post-functionalization of hyperbranched polyurea coatings.

Postfunctionalizable hyperbranched polyurea coatings were prepared by the bulk polycondensation of AB2 monomers on preactivated silicon substrates. As previously shown, AB2 monomers were prepared, comprising a secondary amino group (A) and two blocked isocyanates (B) connected by hexyl spacers, in a single step and in quantitative yields. Covalent anchoring of the coatings on substrates was accomplished by reacting the secondary amino group in the focal point of the polymers with the blocked isocyanates (BIs) of the covalently attached coupling agent.