  The continuum theory of domain structures in ferromagnetic/superconducting
bilayers fails when the equilibrium domain size becomes comparable with
effective penetration depth $\Lambda$. Instead, a lattice of discrete vortices
must be considered. Here, we report our results on the discrete vortex lattices
in stripe domain structures of ferromagnetic/superconducting bilayers. The
vortices are assumed to be situated periodically on chains in stripe domains.
We study the configurations containing up to three chains per domain, and
calculate their equilibrium energies, equilibrium domain size and vortex
positions through a method based on London-Maxwell equations. In equilibrium,
the vortices in the neighbor domains are half-way shifted while they are next
to each other in the same domain. Additionally, more vortex chains per domain
appear spontaneously depending on magnetization and domain wall energy.
