Structural and magnetic characteristics of the intermetallic compounds Ho₂Ni₁₇ and Er₂Ni₁₇

The intermetallic compounds Ho₂Ni₁₇ and Er₂Ni₁₇ crystallize in the hexagonal structure of Th₂Ni₁₇ with lattice parameters a=8.32 AA, c=8.03 AA and a=8.28 AA, c=8.03 AA respectively. The compounds are ferrimagnetic and the effective magnetic moments per formula unit (fu) determined from the paramagnetic region are mu _eff/fu=16.51 mu _B for Ho₂Ni₁₇ and mu _eff/fu=15.27 mu _B for Er₂Ni₁₇, very close to the theoretical values of 16.44 mu _B and 15.16 mu _B. The critical Curie temperatures for the compounds are T_c=587 K (612 K after heat treatment) for Ho₂Ni₁₇ and T_c=572 K (605 K after heat treatment) for Er₂Ni₁₇.