Origin of magnetic anisotropy in doped Ce$_2$Co$_{17}$ alloys

TL;DR

This study uses density functional theory to analyze how doping elements like Fe, Mn, and Zr influence the magnetic anisotropy in Ce$_2$Co$_{17}$ alloys, revealing key electronic-structure mechanisms behind these effects.

Contribution

It provides a detailed understanding of how specific dopants modify magnetic anisotropy in Ce$_2$Co$_{17}$, highlighting Zr as particularly effective for enhancement.

Findings

Replacing Co dumbbell atoms with Fe or Mn increases uniaxial anisotropy.

Zr doping promotes formation of a structure with large uniaxial anisotropy.

Electronic-structure features near the Fermi level drive anisotropy changes.

Abstract

Magnetocrystalline anisotropy (MCA) in doped Ce$_{2}$Co$_{17}$ and other competing structures was investigated using density functional theory. We confirmed that the MCA contribution from dumbbell Co sites is very negative. Replacing Co dumbbell atoms with a pair of Fe or Mn atoms greatly enhance the uniaxial anisotropy, which agrees quantitatively with experiment, and this enhancement arises from electronic-structure features near the Fermi level, mostly associated with dumbbell sites. With Co dumbbell atoms replaced by other elements, the variation of anisotropy is generally a collective effect and contributions from other sublattices may change significantly. Moreover, we found that Zr doping promotes the formation of 1-5 structure that exhibits a large uniaxial anisotropy, such that Zr is the most effective element to enhance MCA in this system.