Influence of changes in electronic structure on magnetocrystalline anisotropy of YCo<sub>5</sub> and related compounds

Author(s)
Ahmad Asali, Josef Fidler, Dieter Suess
Abstract

Density functional theory calculations have been carried out for the hard magnetic compound YCo5 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 Co-atom by Fe or Cu as examples for a magnetic and a nonmagnetic impurity. The comparison between YCo5 and hcp-Co shows the importance of atomic environments and lattice symmetry for a large MAE. The calculations predict that Fe and Cu both reduce MAE, but Fe increases magnetization. Despite lacking 4f-orbitals as compared to SmCo5, YCo5 exhibits a large anisotropy, originating from the contribution of the Co-atoms. We have also shortly studied the influence of 4f-electrons for rare earths R = Pr and Sm on MAE for comparison. YCo4Fe, YCo4Cu, SmCo4Fe and SmCo4Cu are calculated to have MAE values of 2.1MJ/m(3), 2.7MJ/m(3), 19.2MJ/m(3) and 8.2MJ/m(3) at 0 K respectively.

Organisation(s)
Physics of Functional Materials
External organisation(s)
Technische Universität Wien
Journal
Journal of Magnetism and Magnetic Materials
Volume
485
Pages
61-68
No. of pages
8
ISSN
0304-8853
DOI
https://doi.org/10.1016/j.jmmm.2019.04.047
Publication date
09-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
Magnetism, Materials physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/influence-of-changes-in-electronic-structure-on-magnetocrystalline-anisotropy-of-yco5-and-related-compounds(a20a7a23-b008-4f2c-b596-f7e553f5f0be).html