Magnetic characterisation of the ternary carbide ThFe11C x (1.5≤x≤2) by57Fe Mössbauer spectroscopy

A57Fe Mossbauer spectroscopy analysis of the ternary carbide ThFe11C x withx=1.5 and 1.8 has permitted to clearly identify the three different Fe sublattices from their relative abundance. Moreover, direct bonds exist between carbon atoms and iron atoms of one of the three sublattices, yielding a relatively large decrease of the local magnetic moment. A spin reorientation phenomenon (SR), taking place at low temperature, is shown to be of first order type. Both the exchange interactions and magnetocrystalline anisotropy parameters are very sensitive to the carbon stoichiometry. They are analysed for their role on the shifts inTc andTSR respectively.