Experimental verification of the existence and structure of ζ Pu6Fe in a Pu–Ga alloy

A phase belonging to the space group I4/mcm was identified in a Pu–Ga alloy containing trace amounts of Fe and Ni using electron diffraction and energy-dispersive X-ray spectroscopy (EDXS) in a transmission electron microscope. The plane group symmetry of six experimental diffraction patterns showed that the structure of this phase was at least body-centered orthorhombic. Simulated diffraction patterns, generated from the body-centered tetragonal structure of ζ Pu6Fe with the space group I4/mcm, match the experimental diffraction patterns closely. These results present the first crystallographic evidence for the existence of ζ Pu6Fe in a dilute Pu–Ga alloy. The Pu/Fe ratio of the phase yielded by EDXS was 12.5 at.% and the Pu/(Fe + Ni) ratio was 15.9 at.%. These results suggest that Ni substitutes for Fe in the ζ, Pu6Fe lattice.