A MOSSBAUER EFFECT STUDY OF METALLIC COMPOUNDS U6 FE AND PU6 FE AND RELEVANCE OF RESULTS TO THEORIES OF BEHAVIOUR OF ACTINIDE METALS

The intermetallic compounds U6Fe and Pu6 Fe were investigated using Mössbauer spectroscopy. From the Mössbauer point of view the results are straightforward; quadrupole pairs are seen in both materials at room temperature and low temperatures. Low temperature values for the splittings were 0.074 cm/sec for U6Fe and 0.083 cm/sec for Pu6Fe; the corresponding room temperature values were 0.069 and 0.073 cm/sec. Both quadrupole splittings and isomeric shift values are characteristic of Fe in the metallic state. Recent electrical resistivity work has established that the temperature curves for Pu6Fe and Pu metal are qualitatively very similar. In view of this investigation and our Mössbauer results we would be inclined to reject the hypothesis that Pu undergoes an antiferromagnetic transition at low temperatures. However, the situation is complex, and some space is devoted to a review and appraisal of the theories proposed to explain the properties of this most unusual metal. © 1969.