ELEMENTARY DIFFUSION JUMP OF IRON ATOMS IN INTERMETALLIC PHASES STUDIED BY MOSSBAUER-SPECTROSCOPY .1. FE-AL CLOSE TO EQUIATOMIC STOICHIOMETRY

We have studied the quasielastic broadening of the Fe-57 Mossbauer res onance in the intermetallic compound FeAl in order to determine the di ffusion jump mechanism of the Fe atoms. From the angular dependence of the line broadening relative to an oriented single crystal we deduce that the Fe atoms jump effectively to different neighbour sites on the Fe sublattice. The jump is, however, not a direct one, but rather a c ombination of a jump into a nearest neighbour vacancy-leading to short -time occupation of an antistructure site on the Al sublattice-and a j ump into a vacancy back on the Fe sublattice.