Band structure and ordering of magnetic superlattices

The unit cell of a superlattice which contains two multiplane layers corresponding to two different constituent atoms, one of which is a long-range magnetic rare-earth metal, is represented along the superlattice direction by square-well potentials of appropriate depths. The electronic band structure of this bilayer is obtained numerically. The variation is charge density within the bilayer is discussed. The information so obtained allows also the magnetic ordering of the superlattice system to be determined by established the variation in the RKKY exchange interaction with distance. Results for this simple model show encouraging agreement with experimental evidence that the type of ordering is affected by the thickness of the magnetically inert multiplane layer and that long-range magnetic coherence may exist in these structures.