Ab initio local-spin-density study of oscillatory exchange coupling and spin density waves in Fe/Cr multilayers

The interlayer exchange coupling and the magnetic structure of bcc (001) Fe/Cr multilayers have been studied using a first-principles self-consistent tight-binding linear-muffin-tin-orbital method in the atomic sphere approximation. A generalized gradient approximation to the exchange correlation potential was used. Antiferromagnetic coupling between neighboring Fe layers is found to be energetically favorable for an even number of monolayers in the Cr spacer, while ferromagnetic coupling is preferred for an odd number of monolayers. Also it is found that for certain Cr thicknesses incommensurate spin density waves with different wavelengths coexist. (C) 2000 American Institute of Physics. [S0021-8979(00)95208-3].