WL
W. Lohstroh
12 records found
1
MgHx thin films are grown by activated reactive evaporation in a Molecular Beam Epitaxy system fitted with an atomic hydrogen source. During deposition the electrical and optical properties are measured in-situ. The structural properties are determined ex-situ by Atomic Force Mic
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The hydrogenation of metallic Mg2 Ni films was shown to proceed via a self-organized double layering of transparent Mg2 NiH4 and metallic Mg2 NiH0.3. For stoichiometries departing from Mg2 Ni we conclude from optical reflection, transmission and electrical measurements that the h
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The optical switching from shiny metallic to "black" absorbing states of 30 nm Mg2Ni/50 nm TM/10 nm Pd (TM = Ti, V, Cr, Mn, Fe, Co, Ni, Pd) trilayer thin films upon hydrogenation is used to determine the hydrogen absorption/desorption kinetics at moderate H2 pressure and room tem
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Mgy Ni (2 ≤ y ≤ 10) thin films covered with a Pd cap layer are hydrogenated in 1 05 Pa H2 between room temperature and 80 ° C and their dielectric function over(ε, ̃) is determined from reflection and transmission measurements. The hydrogenated Mg
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Hydrogen absorption by a thin Mg2Ni film capped with Pd results in the nucleation of the Mg2NiH4 phase at the film/substrate interface. On further hydrogenation, a self-organized two-layer system consisting of a Mg2NiH0.3/Mg2NiH4 bottom-layer and a Mg2NiH0.3 top-layer is formed.
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Mg2NiH4 thin films have been prepared by activated reactive evaporation in a molecular beam epitaxy system equipped with an atomic hydrogen source. The optical reflection spectra and the resistivity of the films are measured in situ during deposition. In situ grown Mg2NiH 4 appea
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A triple layer thin film (30 nm Mg2Ni/100 nm Ti/10 nm Pd sputtered on glass) switches reversibly from a shiny metallic to a "black" state upon exposure to moderate hydrogen pressure (≈5.103 Pa). This black state resembles that obtained in thick Mg2NiHx layers and has the great ad
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A novel optical technique to measure catalytic activity for hydrogen sorption is presented. The catalytic activity of the noble metals of Pd, Ni, Cu and Ag is studied as function of pressure and temperature. The uptake rate is limited by chemisorption as deduced by modelling kine
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Hydrogen absorption by a Pd capped thin Mg2Ni film results in the nucleation of the Mg2NiH4 phase at the film/substrate interface and thus induces a self-organized two-layer system. This leads to the optical black state in Mg2Ni thin films upon hydrogenation. This unusual hydroge
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Ti-catalyzed Mg(AlH4)2
A reversible hydrogen storage material
Mg-Al thin films with a compositional gradient are co-sputtered from off-centered magnetron sources and capped with a thin Pd layer. We study their hydride formation by monitoring their optical transmission during hydrogenation under defined pressure and temperature conditions. W
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Thin films of Mg2NiHx which exhibit a remarkable black state with low reflection over the entire visible spectrum were investigated. The films show zero transmission and a low electrical resistivity. It was shown that such a black state is not explicable for a homogeneous layer.
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