INITIAL ROTATIONAL SUSCEPTIBILITY OF EXCHANGE-COUPLED PERMALLOY COPPER COBALT MULTILAYERS

Exchange coupled Permalloy/Copper/Cobalt multilayers are observed by K err microscopy. The stability of 180-degrees walls is investigated by applying fields transverse to the initial saturation field. The experi ments show that the anisotropy is not as small as previously assumed, but is determined by the initial field. In contrast to the samples wit h ferromagnetic coupling, the preexisting walls in antiferromagnetical ly coupled samples can easily be annihilated using transverse fields. This can be explained by particular combinations of coupling strength and anisotropy.