In situ observation of nickel as an oxidizable electrode material for the solid-electrolyte-based resistive random access memory Appl. Phys. Lett. 102, 053502 (2013) Probing the hydrogen equilibrium and kinetics in zeolite imidazolate frameworks via molecular dynamics and quasi-elastic neutron scattering experiments J. Chem. Phys. 138, 034706 (2013) Experimental evidence of superionic conduction in H2O ice J. Chem. Phys. 137, 194505 (2012) The role of Anderson-Gruneisen parameter in the estimation of self-diffusion coefficients in alkaline earth oxides J. Appl. Phys. 112, 096101 (2012) Proton conduction related electrical dipole and space charge polarization in hydroxyapatite

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Self-diffusion was studied in magnetron sputtered nitrogen-rich amorphous compounds of the system Si-C-N by using nitrogen as a model tracer. As shown by infra-red spectroscopy a transient metastable region exists, where the structure of the material can be visualized as silicon nitride tetrahedra which are connected by carbo-diimide (-N¼C¼N-) bonds to a three dimensional amorphous network. In this region diffusion studies are carried out by neutron reflectometry and isotope multilayers as a function of annealing time, temperature and chemical composition. Low diffusivities between 10 À20 and 10 À24 m 2 /s were found. In the metastable region, diffusion is faster than diffusion in amorphous silicon nitride by 1 to 2 orders of magnitude, while the activation enthalpies of diffusion between 3.1 and 3.4 eV are the same within error limits. This can be explained by the fact that the diffusion mechanism along SiN 4 tetrahedra is identical to that in amorphous silicon nitride, however, the carbo-diimide bonds seem to widen the structure, allowing faster diffusion. A correlation between diffusivities and the number of carbo-diimid bonds present in the material is found, where the highest diffusivities are observed for materials with the highest number of carbo-diimid bonds, close to the composition Si 2 CN 4. V

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