Results of crystal-structure and magnetic studies of solid solutions between a 5f-band metamagnet UCoAl and ferromagnets URhAl and UIrAl are reported. The UCo1-xRhxAl system exhibits a continuous solubility with a monotonous dependence of lattice parameters. For the UCo1-xIrxAl compounds we observe this behaviour only for concentrations close to parent compounds, i.e. at x≤0.2 and x≥0.8, leaving the alloys with intermediate concentrations structurally heterogeneous. In the common solubility region lattice parameters in both systems are nearly identical. Also in magnetism, Rh and Ir substitutions for Co yield analogous effects. Ferromagnetism is stabilised for x>0.1 and the Curie temperature and the spontaneous moment exhibits qualitatively similar concentration dependence. These results imply similar evolution of electronic structure involving variations of the 5f-ligand hybridization due to Rh and Ir substitutions.
- Uranium intermetallics