We investigate force formulae for two rigid magnetic bodies in dependence on their mutual distance. These formulae are derived
as continuum limits of atomistic dipole–dipole interactions. For bodies that are far apart in terms of the typical lattice
spacing we recover a classical formula for magnetic forces. For bodies whose distance is comparable to the atomistic lattice
spacing, however, we discover a new term that explicitly depends on the distance, measured in atomic units, and the underlying
crystal lattice structure. This new term links the classical force formula and a limiting force formula obtained earlier in
the case of two bodies being in contact on the atomistic scale.
Communicated by A. Mielke