Spin canted magnetic polaritons in thin films

We study the bulk and surface magnetic polariton modes that propagate in thin antiferromagnetic films, whose thickness is much larger than the interatomic distances. We consider the presence of an external magnetic field applied perpendicular to the easy axis of the magnetic material. The presence of this field gives rise to an interesting geometry where the spins are rotated through a canting angle θ. The magnetic polariton spectra are presented numerically for a variety of layering patterns, with interesting profiles. We confine our discussion to uniaxial antiferromagnets fluorides which have a body-centered tetragonal (or rutile) structure (e.g. XF2, with X=Mn or Fe).