  By understanding the small easy axis magnetocrystalline anisotropy energy
(MAE) of hexagonal Ce2Co17, an attempt has been made to improve anisotropy and
consequently to obtain better characteristics for a high energy permanent
magnet via site selective substitutional doping of Ce/Co with suitable
elements. The present calculations of the electronic and magnetic properties of
Ce2Co17 and related substituted compounds have been performed using the full
potential linear augmented plane wave (FPLAPW) method within the generalized
gradient approximation (GGA). Sm-substituted compounds were simulated using
Coulomb corrected GGA (GGA+U) to provide a better representation of energy
bands due to the strongly correlated Sm-f electrons. The formation energies for
all substituted compounds are found to be negative which indicate their
structural stability. Of the substitutions, Zr substitution at the Co-dumbbell
site enhances uniaxial anisotropy of Ce2Co17. Furthermore, Sm-substitution at
Ce-2c sites favors incremental MAE whereas a La-substitution at both 2b- and
2c-sites depletes the tiny MAE in Ce2Co17. These observed trends in the MAE
have been examined in terms of contributions from various electronic states.
Finally, Ce2Zr2Co15 and SmCeCo17 are foreseen as suitable materials for
designing permanent magnets derived from the crystal lattice structure of
hexagonal Ce2Co17.
