We report on the properties of a new air-stable nanowire material with the chemical formula Mo6S3I6. The distinguishing features of the material are rapid one-step synthesis, easy isolation and controllable dispersion into small-diameter wire bundles. Elemental analysis, x-ray diffraction, thermogravimetry, differential thermal analysis, Raman scattering and electron microscopy were used to characterize the material.

Large amounts of Li ions can be electrochemically intercalated into and controllably released by the channels between individual molybdenum selenide nanotubes (see Figure), forming the basis for a promising safe new battery electrode material. The use of dichalcogenide nanotubes rather than the more usual carbon is shown to have important advantages.

We present Raman scattering and scanning tunnelling microscopy (STM) measurements on hydrogen plasma etched single-wall carbon nanotubes (SWNTs). Interestingly, both the STM and Raman spectroscopy show that the metallic SWNTs are dramatically altered and highly defected by the plasma treatment. In addition, structural characterizations show that metal catalysts are detached from the ends of the SWNT bundles. For semiconducting SWNTs we observe no feature of defects or etching along the nanotubes. Raman spectra in the radial breathing mode region of plasma-treated SWNT material show that most of the tubes are semiconducting. These results show that hydrogen plasma treatment favours etching of metallic nanotubes over semiconducting ones and therefore could be used to tailor the electronic properties of SWNT raw materials.

Spin ordering in the low-temperature magnetic phase is directly linked to the orientational ordering of C(60) molecules in organically doped fullerene derivatives. Electron spin resonance and alternating current susceptometry measurements on tetrakis(dimethylamino)ethylene-C(60) (TDAE-C(60)) (Curie temperature T(c) = 16 kelvin) show a direct coupling between spin and merohedral degrees of freedom. This coupling was experimentally demonstrated by showing that ordering the spins in the magnetic phase imprints a merohedral order on the solid or, conversely, that merohedrally ordering the C(60) molecules influences the spin order at low temperature. The merohedral disorder gives rise to a distribution of pi-lectron exchange interactions between spins on neighboring C(60) molecules, suggesting a microscopic origin for the observed spinglass behavior of the magnetic state.

The ESR spectra of a TDAE 1 -C 2 60 single crystal show the existence of antiferromagnetic (AFM) correlations between the unpaired spins on neighboring C 2 60 ions along the c axis and spin canting which leads, below T c , to weak ferromagnetism along a direction perpendicular to the c axis. This suggests that a Dzyaloshinsky-Moriya type mechanism is responsible for ferromagnetic ordering rather than itinerant ferromagnetism. The incomplete orientational ordering of the C 2 60 ions leads to a distribution of exchange coupling constants resulting in spin-glass type behavior which coexists with long range ferromagnetic ordering below T c . The observation of AFM correlations may help to understand why the same basic molecule C 60 can support such different phenomena as ferromagnetism (in TDAE-C 60 ) and superconductivity (in, e.g., K 3 C 60 ).

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The ESR and NMR lines in powder samples of TDAE- C 60 do not show the expected frequency shifts due to long range ordering in the low temperature magnetic phase, but instead show only a relatively small line broadening below Tc=16 K. The temperature dependence of the lineshapes in ESR, the absence of a spontaneous magnetization as well as other magnetic properties suggest that the magnetic ordering below Tc=16 K is local and random, i.e. spin-glass like, rather than ferromagnetic. The possible finite-particle-size effects and possible microscopic mechanisms for the observed magnetic behavior are discussed.