LAUSR

Abstract Density functional theory calculations have been carried out for the hard magnetic compound Y C o 5 and its related phases. The calculations provide a straightforward but accurate method, as reflected in good agreement obtained with experimental results in terms of saturation magnetization and magnetocrystalline anisotropy energy (MAE). For the calculations we used the projector augmented wave method with GGA-PBE approximation and included spin-orbit coupling and ( U , J ) potentials, which are calculated to convergence. It is shown that these properties are influenced by the crystal structure and atomic distances, hence the crystal structures have been optimized and relaxed. The influence of changes in symmetry, distances and lattice parameters are studied, as well as the effect of substituting one C o - atom by F e or C u as examples for a magnetic and a non-magnetic impurity. The comparison between Y C o 5 and hcp - C o shows the importance of atomic environments and lattice symmetry for a large MAE. The calculations predict that F e and C u both reduce MAE, but F e increases magnetization. Despite lacking 4 f - orbitals as compared to S m C o 5 , Y C o 5 exhibits a large anisotropy, originating from the contribution of the C o - atoms. We have also shortly studied the influence of 4 f - electrons for rare earths R = P r and S m on MAE for comparison. Y C o 4 F e , Y C o 4 C u , S m C o 4 F e and S m C o 4 C u are calculated to have MAE values of 2.1 M J / m 3 , 2.7 M J / m 3 , 19.2 M J / m 3 and 8 . 2 M J / m 3 at 0 K respectively.