Expanded h.c.p. Fe Structure in (0001) Fe/Ru Superlattices

Abstract

Fex/Ruy hexagonal close-packed superlattices have been grown by MBE with various layers thickness 4 ⩽ x ⩽ 12 Å and 4 ⩽ y ⩽ 52 Å. The superlattices show fully h.c.p. structure with sharp interfaces and with a periodic modulation along the [0001] growth axis. The h.c.p.-Fe layers correspond to a specific volume of 12.5 Å3 per Fe atom, much larger than in regular close packed phases (11.3 Å3), which is likely related to a high-spin state for Fe.