High pressure studies of UFe₅Al₇ and UFe₇Al₅ actinide compounds

The ternary inter-metallic compounds, UFe₅Al₇ and UFe₇Al₅, crystallize in a tetragonal ThMn₁₂ type structure. In the as-cast samples a residual phase of FeAl (∼2%wt) was identified in the grain boundaries. The amount of the residual cubic phase of FeAl was determined by Rietveld analysis and reduced by the annealing process. UFe₅Al₇ and UFe₇Al₅ maintain the tetragonal symmetry as a function of pressure, while FeAl keeps the cubic structure as was determined by the Rietveld analysis. The volume-pressure curve calculated from the X-ray analysis gives V/V₀=0.87 for UFe₅Al₇ at 26.0 GPa and 0.89 at 24.6 GPa for UFe₇Al₅. (author)