A laminate structure is disclosed comprising multiple ferromagnetic layers
achieving incoherent reversal while maintaining good SNR. A high magnetic
moment density, low anisotropy field material may form a thin overlayer
deposited over a high-anisotropy media layer. The media layer may have a
lower magnetic moment density than the overlayer and have decoupled
magnetic grains. A coupling layer may be interposed between the overlayer
and the media layer to modulate the exchange there between, thereby
reducing the pass-through of noise while still promoting incoherent
reversal to achieve reduced write energy requirements.