We have designed and constructed a custom far-infrared Fourier transform spectrometer using an antenna-coupled bolometer as a detector. The active element of the detector is a superconducting niobium microbridge, and the far-infrared signal is coupled to the microbridge via a planar antenna mounted on a hyperhemispherical silicon lens. The spectrometer uses a broadband blackbody source with fre...

While the superconducting community has developed various techniques for the fabrication of nanoscale hot electron bolometers (HEB), the basic structure of an HEB microbridge has been fairly consistent. A typical HEB used in a cryogenic terahertz mixer consists of a thin strip of superconductor contacted on opposite ends by small metal contact pads in a planar configuration. Both the physics an...

The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3-δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm2 in a symmetrical cell an...

Superconductors with periodically ordered mesoporous structures are expected to have properties very different from those of their bulk counterparts. Systematic studies of such phenomena to date are sparse, however, because of a lack of versatile synthetic approaches to such materials. We demonstrate the formation of three-dimensionally continuous gyroidal mesoporous niobium nitride (NbN) super...

Vanadium-niobium oxide catalysts containing variable amounts of vanadium and prepared by coprecipitation were investigated using 51V solid-state NMR. It was found that, in samples containing less than about 8 mol % V2O5, vanadium occurs in three different oxygen environments: in isolated tetrahedra, in comer-sharing tetrahedra (pyrovanadate), and in distorted octahedra. The number of octahedral...