In the title of this paper (and also in several places in the text), the chemical notation for the orthorhombic semiconducting iron disilicide is given incorrectly. In the whole paper, the chemical formula “β-FeSi2.5” should be replaced by the formula “β-FeSi2”.

Results of magnetization and magnetic susceptibility measurements on undoped and Co-doped FeSi2.5 single crystals are presented. The temperature dependence of the magnetic susceptibility of the Co-doped sample in the range of 5–300 K can be explained by temperature-dependent contributions due to paramagnetic centers and the carriers excited thermally in the extrinsic conductivity region. The values of the paramagnetic Curie temperature and activation energy of the donor levels were estimated. It is also shown that the magnetic susceptibility of Co-doped samples cooled in zero external field and in a field are different. This resembles the properties of spin-glasses and indicates the presence of coupling between magnetic centers.

Epitaxial ReSi1.75 thin films of variable thickness between 15nm and 150nm have been prepared in an one step process by Facing Target Sputtering (FTS) onto heated (100) and (111)Si and SOS wafers. The epitaxial relations and film structure have been investigated by Xray diffraction and transmission electron microscopy. Epitaxial growth was found at a substrate temperature of 1070K. Thermoelectric properties were measured between 100K and 450K and compared to the transport behavior of bulk ReSi1.75 and polycrystalline films. A distinct dependence of both the conductivity and thermopower was found on the film thickness, on unintentional doping and on the film structure. The results show that epitaxial ReSi1.75 films prepared by FTS can be a basis for further investigations of thermoelectric silicide/silicon multilayers.

Polycrystalline ß-FeSi2 layers prepared by codeposition of Si and Fe on cold and hot Si substrates and ß-FeSi2, crystals grown by chemical vapor transport were investigated. Resistivity and Hall effect measurements revealed the p-type conductivity of undoped material and the influence of some dopants of the iron group. The activation energy of a Cr-related acceptor was determined to about 85 meV. The mobility data were found to depend significantly on the purity of the preparation process.