A magnetic recording medium includes a substrate, an underlayer, a lower magnetic
layer formed on the underlayer, an intermediate layer, and an upper magnetic layer
formed on the intermediate layer. The intermediate layer is typically Ru, and promotes
antiferromagnetic coupling between the upper and lower magnetic layers. The upper
and lower magnetic layers are typically Co alloys. The lower magnetic layer has
a high saturation magnetization Ms to promote high exchange coupling between the
upper and lower magnetic layers. The dynamic coercivity of the lower magnetic layer
is lower than the exchange field to ensure rapid switching of the lower magnetic layer.
