The investigation of many stoichiometric variations involving large numbers of combinations of elements offers a means to discover a hydride with optimal properties. We introduce the use of spatially resolved infrared imaging as a high throughput hydrogen storage candidate screening technique. Analysis is presented of a sample that consists of 16 separate Mg-Ni-Fe ternary pads and 32 Mg-Ni or Mg-Fe binary pads. Hydrogen sorption related emissivity changes observed indicate a substantial decrease in hydriding temperatures, which sensitively depends on composition.

The first direct electrical resistance measurements performed on a single carbon nanotube bundle from room temperature down to 0.3 K and in magnetic fields up to 14 T are reported. From the temperature dependence of the resistance above 2 K, it is shown that some nanotubes exhibit a semimetallic behavior akin to rolled graphene sheets with a similar band structure, except that the band overlap, Δ ≈ 3.7 meV, is about 10 times smaller than for crystalline graphite. In contrast to graphite which shows a constant low-temperature resistivity, the nanotubes exhibit a striking increase of the resistance followed by a broad maximum at very low temperatures. A magnetic field applied perpendicular to the sample axis decreases the resistance. Above 1 K, this behavior is consistent with the formation of Landau levels. At lower temperatures, the resistance shows an unexpected drop at a critical temperature which increases linearly with magnetic field. These striking features could be related to the unique quasi-one-dimensional structure of the carbon nanotubes.

In situ Raman spectra were taken, between 800 and 1200 cm−1, on films of polypyrrole during both the electrochemical growth and the reduction reactions. During the reduction reaction we observed a frequency shift of approximately 10 cm−1 of two in-plane vibrational modes. We attribute these shifts to the bond conjugational defects induced by doping and undoping of the polypyrrole films. A quantitative model for this phenomenon based on normal mode calculations is presented. The electrical conductivity and thermopower of polypyrrole doped with tetrafluoroborate and iron chloride ions is also reported for temperatures between 10 and 350K.