Formation of Mn doped iron silicides by ball milling

J. DESIMONI, S. M. COTES, M.A. TAYLOR, M.R. MERCADER

Montpellier, Francia

Congreso; International Conference on the Aplication of the Mossbauer Effect. ICAME; 2005

The Fe-Si system is complex because, depending on the experimental conditions of synthesis, several stable and metastable phases can be produced. Non-equilibrium processing techniques like mechanical alloying allow the formation of compounds and metastable phases which are not accessible by conventional techniques. In particular, semiconducting b-FeSi2 disilicide have attracted the attention in the last years due to its technological potential in the field of optoelectronic and as a suitable material for thermoelectric conversion. The doping with Mn poses intriguing fundamental issues related to the occurrence of metastable phases arising from the structural differences between iron and manganese silicides and related to the occupancy of the two non-equivalent Fe sites in the b-FeSi structure, as well.              A study of the sequence of phase formation in powders of stoichiometric Fe1-xMnxSi2 (0.00 £ x £ 0.12) mixtures is carried on. Samples are prepared by mechanical alloying at room temperature in Ar atmosphere using a horizontal mill. Preliminary results obtained by Mössbauer Spectroscopy and X-ray diffraction are presented here.