Magnetization dynamics: A study of the ferromagnet/antiferromagnet interface and exchange biasing

We use a method which employs a dynamic calculation of magnetization motion to find both the static configuration and the spin wave excitations in a f erromagnet/antiferromagnet layered structure. Our results for the static st ructure are similar to those found in Koon's model; i.e., in zero applied f ield the ferromagnet points perpendicularly to the easy axis of the antifer romagnet, and the surface spins of the antiferromagnet are in a surface spi n flop configuration. The calculated hysteresis curve for this structure sh ows a small exchange bias, in agreement with typical experimental results. We explore how this bias depends on the parameters of the antiferromagnet a nd on the nature of the interface coupling. We further examine models for a ntiferromagnets with both compensated and uncompensated surfaces. We show t hat the structure calculated by Koon is unstable at higher reversed magneti c fields but that this instability can be suppressed by an easy-plane aniso tropy. (C) 1999 American Vacuum Society. [S0734-2101(99)00404-2].