J. L. Dormann

Interface properties in granular compound films studied by Mössbauer spectroscopy

Abstract The nature of iron atoms in granular iron compounds (FeSiO 2 , FeAl 2 O 3 , FeZrO 2 ) was studied by the Mossbauer effect. Granular compounds with a low concentration of iron are almost amorphous and exhibit a large distribution of hyperfine parameters. Superparamagnetism occurs, the transition temperature depending on the diameter of the grains. The behaviour of iron in granular samples depends on the nature of the insulating matrix.

Vapor growth of thio- and selenospinels

Abstract HC1+Cl 2 was found to be a suitable transport agent to grow thio- and selenospinel single crystals. The speed of deposition has been calculated from partial pressures of gaseous species in equilibrium with the solid.

Chemical transport of FeCr2S4

Abstract FeCr 2 S 4 single crystals were grown by vapor transport in a closed system using first Cl 2 and a mixture of HCl+Cl 2 . Thermodynamic calculations show that chemical transport is only possible using HCl+Cl 2 as transport agent. Composition of the gas phase in equilibrium with the solid is derived from thermodynamic calculations.