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O. Bartels, K.D. Becker

A High-Temperature Mössbauer Study of the Iron Nitrides

Keywords: Mössbauer spectroscopy, Iron Nitrides, Structure, Nonstoichiometry

Mössbauer spectra of the iron nitrides have been measured at room temperature and at 550ºC. In the case of the room temperature spectrum of γ´-Fe₄N, a fit strategy is reviewed which accounts for two spectroscopically inequivalent iron Fe(1) sites due to the simultaneous presence of magnetic and quadrupolar interactions. In contrast, the high-temperature spectra of γ´-Fe₄N allow for the direct determination of the quadrupolar interactions at Fe(1) sites. In the case of ε-Fe₃N_1+x, the stoichiometry dependent magnetically-split room temperature spectra demonstrate the extensive ordering of nitrogen in the compound. At 550ºC, spectra have been measured at various defined thermodynamic conditions of controlled nitrogen activity. The quadrupole-split spectra high-temperature are discussed in relation to structure and disorder of the material. In particular, it is shown that the composition dependent high-temperature spectra of ε-Fe₃N_1+x can be modelled in the framework of a simple two-site model.

Zeitschrift für Physikalische Chemie, Oldenbourg Wissenschaftsverlag

Print ISSN: 0942-9352
Volume: 221, 11/2007
Pages: 1509 - 1524

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