variable temperature ⁵⁷fe-mössbauer spectroscopy study of nanoparticle iron carbides

Near-phase-pure nanoparticle iron carbides (Fe₃C and Fe₅C₂) were synthesised. Debye model calculations were used with hyperfine parameters gathered by ⁵⁷Fe Mössbauer spectroscopy within a temperature range of 10 K to 293 K, with analysis providing Debye temperatures of 422 K and 364 K for two Fe sites in Fe₅C₂ and 355 K for ferromagnetic Fe₃C. The intrinsic isomer shifts were calculated as 0.45 mm s⁻¹ and 0.43 mm s⁻¹ for iron sites 1 and 2 respectively in Fe₅C₂ and 0.42 mm s⁻¹ for Fe₃C. Recoil-free fractions for the two iron sites were also calculated at f300 0.785 and 0.726 for site 1 and 2 respectively.