M. Vanschilfgaarde et Wa. Harrison, OSCILLATORY EXCHANGE COUPLING - RKKY OR QUANTUM-WELL MECHANISM, Physical review letters, 71(23), 1993, pp. 3870-3873
The exchange coupling in multilayers of iron and chromium is calculate
d in the local spin density approximation, as a function of the Fe mag
netic moment. We find a short-period and a long-period oscillation, wh
ich we attribute to a harmonic of the short period. For small moments,
the interlayer coupling is found to be bilinear in the Fe moments, as
assumed in RKKY theory. For moments appropriate to real iron the coup
ling tends to saturate, as assumed in quantum-well models, demonstrati
ng that the quantum-well model more correctly describes the real iron-
chromium system, though both models give correct periods of the oscill
ation.