Oscillatory exchange coupling in Fe/Cr multilayers

First-principles calculations of the reflection probabilities for Fermi-surface electrons at Cr/Fe interfaces are used to compute the strength of the oscillatory exchange coupling in Cr/Fe multilayers. These calculations show that critical spanning vectors across the N-centered ellipsoids of the Cr Fermi surface cause the long-period coupling for (001), (110), and (211) interfaces. The periods of these spanning vectors, when extracted from the experimental Fermi surface, agree with experimentally measured periods. {} 1996 The American Physical Society.