BRILLOUIN LIGHT-SCATTERING STUDY OF MAGNETIC COUPLING IN COFE MN/COFE/

Coupling mechanisms between Co0.75Fe0.25 films separated by Mn layers are investigated using Brillouin light scattering from thermal spin wa ves. Trilayers of CoFe/Mn/CoFe, grown by molecular-beam epitaxy, were studied with Mn thicknesses between 6 and 30 Angstrom. Spin-wave excit ations corresponding to acoustic and optic modes in double layer magne tic structures were observed, and allowed a determination of a strong magnetic coupling between the CoFe films. Spin-wave frequencies were e xamined as functions of applied field, Mn film thickness, and temperat ure. A microscopic model is used to examine magnetic order in a ferrom agnet/antiferromagnet/ferromagnet structure. Discrepancies between the data and predictions of the microscopic model provide evidence for a twist in the FeCo spins that extends into the ferromagnet layer. [S016 3-1829(98)10117-0].