Writability enhancement using exchange spring media

We have investigated the magnetic reversal and recording properties of layered ferromagnetically exchange coupled (or exchange spring) structures made of a hard layer and a soft layer. The hard layer is a longitudinal antiferromagnetically-coupled (AFC) media which is exchange coupled to a soft CoCrX layer via a CoRu interlayer. We find that optimizing the CoCrX and CoRu layer thicknesses is critical to achieve optimum improved writability while maintaining the media signal to noise ratio (SNR). Furthermore although we successfully decrease substantially the media coercive field (Hc) of these exchange spring structures, the energy barrier K_uV appears unchanged. Finally, we show that these structures have the potential of improved SNR.