SURFACE-POLARITONS AND ATTENUATED TOTAL-REFLECTION SPECTRA OF LAYERED ANTIFERROMAGNETS IN THE FARADAY CONFIGURATION

A detailed theoretical discussion is presented for the surface polaritons and attenuated total reflection (ATR) spectra of layered antiferromagnets when an applied magnetic field is parallel to the surface and to the propagation direction (i.e. Faraday geometry). Our numerical results for NiO reveal the existence of both bona fide surface polariton and generalized surface modes which were never indicated before in magnetic systems. In addition, the conventional derivation of the rf permeability tenser mu has recently been argued to be incorrect and consequently should be replaced by an alternative derivation that is consistent with macroscopic electrodynamics. We suggest, in view of previous experience on FIR magnetic spectroscopy, that FIR ATR spectroscopy may directly discriminate between the alternative forms for mu. The results are equally valid for a large class of magnetic layered systems including artificial magnetic superlattices with antiferromagnetic coupling.