Fig. 3
From: Expansion of the spin cycloid in multiferroic BiFeO3 thin films
Spin structure as determined from first-principles-based calculations. In a the spin structure in the same geometry as the thin film is shown, with x′ || [001] along the in-plane direction, and z′ || [110] normal to the film plane. Here in a 200 nm film the 18 × 18 × 18 supercell reproduces ~6 full cycloids. b shows the cycloid structure along the \([11\bar 2]\) propagation direction, showing that the Fe spins are almost completely confined to the \((1\bar 10)\) plane
