How antiferromagnetic coupling can stabilize recorded information

Summary form only given. The signal-to-noise ratio requirements for high-density recording media have driven down the grain size of present recording media to the range in which superparamagnetic effects become significant. Antiferromagnetically coupled (AFC) media have been suggested to further reduce the grain size while maintaining thermal stability as well as write-ability of the media. In typical AFC media designs, the stabilization layer can show superparamagnetic behavior. In this report, we analyze the stabilization mechanism of AFC media by calculating the effective energy barrier against magnetization reversal of a pair of anti-ferromagnetically coupled single-domain particles, whereby one of the particles can be superparamagnetic. Due to the interfacial exchange coupling between the grains, the magnetic energy of the stabilization layer is coupled to that of the main layer.