Superhydrophobic ceramic coatings enabled by phase-separated nanostructured composite TiO2-Cu2O thin films.

By exploiting phase-separation in oxide materials, we present a simple and potentially low-cost approach to create exceptional superhydrophobicity in thin-film based coatings. By selecting the TiO2-Cu2O system and depositing through magnetron sputtering onto single crystal and metal templates, we demonstrate growth of nanostructured, chemically phase-segregated composite films. These coatings, after appropriate chemical surface modification, demonstrate a robust, non-wetting Cassie-Baxter state and yield an exceptional superhydrophobic performance, with water droplet contact angles reaching to ~172° and sliding angles <1°.

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films.

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e.

Two-band superconductivity in LaFeAsO0.89F0.11 at very high magnetic fields.

The recent synthesis of the superconductor LaFeAsO(0.89)F(0.11) with transition temperature T(c) approximately 26 K (refs 1-4) has been quickly followed by reports of even higher transition temperatures in related compounds: 41 K in CeFeAsO(0.

Spontaneous symmetry-breaking vortex lattice transitions in pure niobium.

We report an extensive investigation of magnetic vortex lattice (VL) structures in single crystals of pure niobium with the magnetic field applied parallel to a fourfold symmetry axis, so as to induce frustration between the cubic crystal symmetry and hexagonal VL coordination expected in an isotropic situation. We observe new VL structures and phase transitions; all the VL phases observed (including those with an exactly square unit cell) spontaneously break some crystal symmetry. One phase even has the lowest possible symmetry of a two-dimensional Bravais lattice.

High-performance high-TC superconducting wires.

We demonstrated short segments of a superconducting wire that meets or exceeds performance requirements for many large-scale applications of high-temperature superconducting materials, especially those requiring a high supercurrent and/or a high engineering critical current density in applied magnetic fields. The performance requirements for these varied applications were met in 3-micrometer-thick YBa2Cu3O(7-delta) films epitaxially grown via pulsed laser ablation on rolling assisted biaxially textured substrates. Enhancements of the critical current in self-field as well as excellent retention of this current in high applied magnetic fields were achieved in the thick films via incorporation of a periodic array of extended columnar defects, composed of self-aligned nanodots of nonsuperconducting material extending through the entire thickness of the film.

Metallic normal state of Y1Ba2Cu3O(7-delta).

Flux flow was studied over an entire temperature range down to T approximately 2% of T(c) by using intense pulsed current densities to overcome flux-vortex pinning. The resistivity at high vortex velocities is proportional to B and roughly follows rho approximately rho(n)B/H(c2), with a prefactor of order unity. Contrary to some speculation, rho(n) saturates to a finite residual value as T-->0, indicating a metallic (rho-->finite) rather than insulating (rho-->infinity) normal state, and the vortex dissipation continues to be conventional as T-->0.

Superconductivity in SrCuO2-BaCuO2 Superlattices: Formation of Artificially Layered Superconducting Materials.

Pulsed-laser deposition was used to synthesize artificially layered high-temperature superconductors. Thin-film compounds were formed when the constraint of epitaxy was used to stabilize SrCuO(2)-BaCuO(2) superlattices in the infinite layer structure. Using this approach, two new structural families, Ba(2)Srn-1,Cun+1 O2n+2+delta and Ba(4)Srn-1 Cun+3O2n+6+delta have been synthesized; these families superconduct at temperatures as high as 70 kelvin.