The authors report on fabrication and characterization of a polymeric spin valve with the conjugated polymer regioregular (poly 3-hexylthiophene) (RRP3HT) as the spacer layer. The device structure is La0.67Sr0.33MnO3 (LSMO)/polymer/Co, with half-metallic, spin-polarized LSMO acting as the spin-injecting electrode. The spin valve shows behavior similar to a magnetic tunnel junction though the nonmagnetic spacer layer (∼100nm) is much thicker than the tunneling limit. They attribute this behavior to the formation of a thin spin-selective tunneling interface between LSMO and RRP3HT caused by RRP3HT, chemically attaching to LSMO as observed by x-ray photoelectron spectroscopy measurement. This gives rise to ∼80% magnetoresistance (MR) at 5K and ∼1.5% MR at room temperature. They found that by introducing monolayer of different organic insulators between LSMO and RRP3HT the spin-selective interface is destroyed and the spin injection is reduced. Their results show that organic materials are promising candidates for spintronic applications.

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Amorphous hydrogenated silicon carbonitride (a-Si:C:N:H) films were produced by remote microwave hydrogen plasma CVD (RP-CVD) using (dimethylamino)dimethylsilane as a single-source precursor. The reactivity of the precursor with atomic hydrogen was characterized using (dimethylamino)trimethylsilane as a model compound. The effects of the substrate temperature (T S ) on the kinetics of the RP-CVD process, and the chemical composition and structure of the resulting film, have been investigated. The temperature dependencies of the mass-and thickness-based film growth rates imply that, for a low substrate temperature range (T S = 30±100 C), film growth is limited by desorption of film-forming precursors, whereas in a high substrate temperature range (T S = 100±400 C) film growth is independent of the temperature, and the rate of RP-CVD is masstransport limited. The increase of the substrate temperature from 30 C to 400 C causes the elimination of organic moieties from the film and the formation of a Si±N and Si±C network structure. The films produced at T S = 300 C were found to be dense materials exhibiting excellent morphological homogeneity, high hardness, and an extremely low friction coefficient. In view of these properties, a-Si:C:N:H films produced by RP-CVD seem to be promising coatings for tribological use.

Amorphous hydrogenated silicon carbide (a-SiC:H) films are produced by remote microwave hydrogen plasma (RHP)CVD using triethylsilane (TrES) as the single-source precursor. The reactivity of particular bonds of the precursor in the activation step is examined using tetraethylsilane as a model compound for the RHP-CVD experiments. The susceptibility of a TrES precursor towards film formation is characterized by determining the yield of RHP-CVD and comparing it with that of the trimethylsilane precursor. The effect of substrate temperature (T s ) on the rate of the RHP-CVD process, chemical composition, and chemical structure of the resulting a-SiC:H films is reported. The substrate temperature dependence of the film growth rate implies that film growth is independent of the temperature and RHP-CVD is a mass transport-limited process. The examination of the a-SiC:H films, performed by means of X-ray photoelectron spectroscopy (XPS), elastic recoil detection analysis (ERDA), and Fourier transform infrared absorption spectroscopy (FTIR), reveals that the increase in the substrate temperature from 30 -C to 400 -C causes the elimination of organic moieties from the film and the formation of a Si-carbidic network structure. On the basis of the results of the structural study, the chemistry involved in film formation is proposed.