Electronic Structure of Iron Nitrides Studied by Electron Diffraction. I. γ'-Fe₄N

Abstract

Using the fact that low order reflection intensities in electron diffraction depend strongly on the electronic state of atoms in crystals, the electronic structure of γ'-Fe 4 N was determined by measuring superstructure reflection intensities, which are contributed almost by nitrogen atoms, from a polycrystalline film produced by nitriding evaporated iron film with ammonia-hydrogen gas. The observed superstructure reflection intensities were put on the absolute scale by comparing with higher order main reflection intensities free from the effect of atomic ionization. A detailed analysis lead to the conclusion that the electronic structure is Fe 0 (Fe +1/3 ) 3 N -1 . Although the present structure is different from the models proposed previously for the interpretation of the ferromagnetic properties of γ'-Fe 4 N, it is possible to interpret the magnetic moment distribution equally well. Some discussions are also given about the bonding nature in the nitride.