The itinerant-state magnetocrystalline anisotropy energies (MAE) of RCo5 (R
= Y, La. Pr, Nd. Sm. Gd) have been determined by relativistic density-func
tional calculations in local spin density approximation, with additionally
taking into account orbital polarization. The calculated MAEs are found to
be strongly affected by changes of the lattice geometry (c/a ratio and volu
me) resulting from (a) uniaxial strain in YCo5 and (b) the lanthanide contr
action along the RCo5 series. (C) 2001 Elsevier Science B.V. All rights res
erved.