  We calculate the contribution of the Neel surface anisotropy to the effective
anisotropy of magnetic nanoparticles of spherical shape cut out of a simple
cubic lattice. The effective anisotropy arises because deviations of atomic
magnetizations from collinearity and thus the energy depends on the orientation
of the global magnetization. The result is second order in the Neel surface
anisotropy, scales with the particle volume and has cubic symmetry with
preferred directions [+-1,+-1,+-1].
