High-field 57Fe Mössbauer investigations at up to 13.5T were performed on a series of almost-equimolar alloys, and magnetic measurements were carried out on a 51.8%Fe sample at temperatures of between 4.2 and 295K. It was found that only some 25% of the Fe atoms carried a magnetic moment. This discrepancy could be explained if non co-linear spin-ordering was allowed, and a high density of defects was taken into account. This was typical of alloys, and destroyed translational periodicity. Magnetic moments were observed experimentally only for Fe antistructure atoms and their eight Fe neighbors. This 9-atom cluster had a mean moment which was in reasonable agreement with the results of super-cell (54-atom) calculations. Four sub-spectra were used for the Mössbauer analysis, and were allocated to Fe in the completely ordered B2 structure, to Fe antistructure atoms and to their nearest Fe neighbors, as well as to Fe atoms around a vacancy in the Fe sub-lattice. This analysis permitted the simultaneous determination of the concentrations of both Fe vacancies and Fe antistructure atoms. The derived temperature dependences of both defect types agreed well with thermodynamic model calculations, and accounted for all possible types of point defect.

Magnetic Order and Defect Structure of FexAl1-x Alloys around x = 0.5: an Experimental and Theoretical Study. J.Bogner, W.Steiner, M.Reissner, P.Mohn, P.Blaha, K.Schwarz, R.Krachler, H.Ipser, B.Sepiol: Physical Review B, 1998, 58[22], 14922