Interlayer-coupling magnetism and electronic structure of Fe/Cr(001) superlattices

The electronic structure and magnetism of Fem/Crn(001) superlattices with varying layer thickness (m=1,3 and n=1,3,5,7) were studied using the all-electron total-energy self-consistent linear muffin-tin orbital method based on the local-density approximation. Similar to the Fe/Cr(110) superlattices, (i) there is a strong hybridization between Cr d and Fe d states; (ii) the absolute values of the magnetic moments of the Fe layers are not significantly modified by the intervening Cr layers. The small moment found on the interfacial Cr atoms is aligned antiparallel for 3 Fe layers and parallel for monolayer Fe to the nearest-neighbor Fe moments in the Fem/Crn(001) superlattices, respectively. For the former case the ferromagnetic alignment for the two consecutive Fe layers separated by Cr layers dominates over the antiferromagnetic alignment, whereas a crossover is seen when the number of Cr layers is increased to 5 (or perhaps 3) layers in between a single Fe layer, i.e., a (slightly) lower total energy for the antiferromagnetic state with respect to the ferromagnetic state.