SHORT-RANGE ORDERING IN AMORPHOUS AL90FEXCE10-X

The atomic structure of liquid-quenched amorphous Al90Fe(x)Ce10-x (x = 5, 7) was studied by diffraction method using X-rays from a synchrotron source. The diffraction data were Fourier-transformed to obtain the atomic pair-density function, and were compared with those obtained by the pulsed neutron scattering to determine the Al-Fe and Al-Ce coordination and the extent of compositional short range ordering. The accuracy of the pair-density function, limited by both statistical and systematic errors, is discussed. It was found that both Fe and Ce atoms show strong compositional short range ordering, amounting to 70-80% of the maximum ordering possible. While Ce atoms form a dilute dense random packing substructure, the substructure of Fe atoms and the surrounding Al was found to be substantially different from the random packing.