MAGNONS IN ANTIFERROMAGNETICALLY COUPLED SUPERLATTICES

We present an experimental Brillouin-scattering study of the collectiv e spin-wave modes in antiferromagnetically coupled Fe/Cr(211) superlat tices. We show spectra as a function of external magnetic field, where the field is swept from very small values up to those required to sat urate the sample in the ferromagnetic state. We thus explore excitatio ns in the low-field antiferromagnetic state, the surface spin-hop regi me, the symmetric ''bulk'' spin-flop regime, and the high-field state. The data are compared with theoretical studies based on a description of the collective modes developed previously.