Calculated magnetocrystalline anisotropy of existing and hypothetical MCo5 compounds

The magnetic properties, lattice parameters and formation enthalpies of existing and hypothetical MCo5 compounds (M=Y, La, Th, Mg, Ca and Sr) are calculated within the framework of density functional theory. In these compounds the magnetocrystalline anisotropy energy is dominated by itinerant Co 3d contributions. Band energy calculations suggest that-within in a rigid band picture-anisotropy energies of comparable size to those of hard magnetic materials containing rare earths could be obtained by hole doping of YCo5, e.g. by the substitution of Ca or Mg for Y. This idea is confirmed by the presented total energy calculations. However, the calculated enthalpies of formation suggest that CaCo5 and MgCo5 could only be prepared by non-equilibrium methods.