The phase stability of LaNi5-LaCo5 alloys with the CaCu5 type crystal structure (P6/mmm) has been investigated from first principles, The alloy is computed to form a continuous solid solution. Ferromagnetism increases with Co concentration, in accordance with experimental observations. It is found that Co impurities in LaNi5 have a strong preference for the three-fold degenerate non-basal sites (Ni-II, 3g). This preference persists at high temperatures, as has been observed in actual alloys by neutron scattering. The softness in the c direction is shown to increase with increasing Co concentration in the alloy.
- Electronic total energy calculations
- La-Co-Ni alloys
- Metal hydrides
- Phase diagram