Synthesis and characterization of iron nitrides. An XRD, Mössbauer, RBS and XPS characterization

Abstract

AbstractIn this work, we demonstrate the capability of a dual ion beam sputtering method to obtain iron nitride thin films, FeNx, in a wide composition range (0.1 < x < 0.5) and structures (α′, γ′, ε, ζ, γ″ and γ″′) by controlling the deposition conditions (i.e. deposition rate, flux and energy of the assisting nitrogen ions and substrate temperature). The average composition of the films has been determined by resonant RBS to enhance the nitrogen signal, whereas the structural characterization and the phase identification have been carried out by X‐ray diffraction (XRD) and Mössbauer spectroscopy. We present a thorough and complementary analysis of the XRD and Mössbauer data as a function of the composition of the film for all the iron nitride phases. Furthermore, it is shown that the iron Auger parameter (AP) increases up to 0.8 eV with respect to that for pure α‐Fe when the nitrogen concentration increases up to 46 at.% (i.e. γ″ and γ″′ phases) so that it might serve to analyze samples of unknown composition. Copyright © 2008 John Wiley & Sons, Ltd.