Structural, thermal and magnetic properties of Y2Fe2Si2C

We report detailed investigations on the structural, thermal and magnetic properties of Y₂Fe₂Si₂C over the temperature range 2–300 K using x-ray diffraction, specific heat, ⁵⁷Fe Mössbauer spectroscopy and first-principles calculations. Low temperature measurements show no pronounced anomalies which might signal magnetic ordering of the Fe sublattice at low temperature. Analyses of the specific heat data of Y₂Fe₂Si₂C reveal the presence of a localised Einstein mode, suggesting the importance of an optical contribution to the phonon spectrum of Y₂Fe₂Si₂C. Based on electronic structure calculations, we found a low density of states of the Fe 3d bands at the Fermi level. The corresponding density of states are below the Stoner criterion, thus indicating a non-magnetic state of the Fe atoms in Y₂Fe₂Si₂C, in agreement with the experimental findings.