W. Lohstroh
16 records found
1
Authored
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 ...
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 ...
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 Mg2 ...
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/ ...
The temperature dependent optical properties of certain thin films are used in so-called thermochromic devices. As an alternative to a single layer of, e.g. VO2, which displays a temperature dependent optical transmission, we propose the use of an encapsulated metal ...
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 ...
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 k ...
The structural, thermodynamic and optical properties of Mg2Ni thin films covered with Pd are investigated upon exposure to hydrogen. Similar to bulk, thin films of metallic Mg2Ni take up 4 hydrogen per formula unit and semiconducting transparent Mg2< ...
Mg-Ni-H films as selective coatings
Tunable reflectance by layered hydrogenation
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 ...