  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.
