Isotropic effects in exchange-biased ferromagnetic /antiferromagnetic bilayers

Novel, direction-independent (rotatable) spin-wave frequency modifications in a ferromagnetic layer biased by an antiferromagnetic film, revealed recently with Brillouin light scattering, have been analyzed. Physical conditions needed for the rotatable behaviour observations in epitaxial layers have been presented. The omni-rotatable down-shift, being a function of a spin-wave frequency, was distinguished from the up-shift of spin-wave frequencies induced by the exchange-bias. Additionally, the rotatable anisotropy constant was estimated from the available BLS results.