<i>In situ</i> — High Temperature Mössbauer Spectroscopy of Iron Nitrides and Nitridoferrates

Abstract

Abstract The stoichiometric iron nitrides γ′‐Fe 4 N, ε‐Fe 3 N and ζ‐Fe 2 N were characterized by Mössbauer spectroscopy. The thermal decomposition of ε‐Fe 3 N was studied in‐situ by means of a specially developed Mössbauer furnace. We found ε‐Fe 3 N to γ′‐Fe 4 N and ε‐Fe 3 N x (x ≥ 1.3) as decomposition products and determined the border of γ′/ε transformation at T ≅ 930 K. Mössbauer spectroscopy was applied to study in‐situ the thermal decomposition of the nitridometalate Li 3 [Fe III N 2 ] and the formation of Li 2 [(Li 1‐ x Fe I x )N], the compound with the largest local magnetic field ever observed in an iron containing material. The kinetics of formation and the stability of Li 2 [(Li 1‐ x Fe I x )N] was of particular interest in the present study.