Reflection and transmission by magnetic multilayers

This paper presents the formalism for transmission of normally incident electromagnetic radiation through a finite superlattice of alternating magnetic and non-magnetic layers. It is assumed that the ordering direction and static field, if any, are perpendicular to the interfaces so that the eigenmodes for propagation are the states of circular polarization. The transmission and reflection coefficients are expressed in terms of the transfer matrix for propagation across a unit cell of the superlattice. The results are illustrated for a ferromagnet/non-magnet superlattice. Prominent features are seen related first to resonances in the magnetic permeability and second to the stop bands of the Bloch waves of the superlattice. In transparency regions, fringes occur due to the overall thickness of the superlattice.