Boltzmann distribution of bond orientations and perpendicular anisotropy in amorphous rare-earthtransition-metal films

We show that the Boltzmann distribution of bond orientations induced by a perpendicularly magnetized layer in the growth process of an amorphous rare-earthatransition-metal film always leads to the bulk perpendicular magnetic anisotropy, irrespective of the specific functional form of the bond energy. The initial perpendicularly magnetized layer can arise from the surface anisotropy produced by antiparallel dipoles or even from spontaneous magnetization.