Mossbauer Spectroscopy of Iron Carbides: From Prediction to Experimental Confirmation
The Mossbauer spectroscopy of iron carbides (a Fe, g' FeC, e Fe2C, z Fe2C, kh Fe5C2, h Fe7C3, th Fe3C, o Fe7C3, g' Fe4C, g' Fe4C, and a' Fe16C2) is predicted utilizing the all electron full potential linearized augmented plane wave (FLAPW) approach across various functionals from LDA to GGA (PBE, PBEsol, and GGA U) to meta GGA to hybrid functionals. To validate the predicted MES from different functionals, the single phase kh Fe5C2 and th Fe3C are synthesized in experiment and their experimental MES under different temperature (from 13 K to 298 K) are determined. The result indicates that the GGA functional (especially, the PBEsol) shows remarkable success on the prediction of Mossbauer spectroscopy of a Fe, kh Fe5C2 and th Fe3C with delocalized d electrons. From the reliable simulations, we propose a linear relationship between Bhf and mB with a slope of 12.81 T/mB for iron carbide systems and that the proportionality constant may vary from structure to structure.
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