Noise Characteristics in Magnetic Recording Media

Magnetic recording media are designed to provide stability of the recorded information to as high a spatial density as possible.The magnetic noise can be characterized into two primary forms: transition noise and "DC" noise. Transition noise arises from the bit to bit randomness of the "zig-zag" wall. This noise is "non-stationary" because it is local and depends on the transition density. The "DC" noise is "stationary" and arises from the grains independent of whether a transition is written or not. Double layer media can help to reduce the noise even further. Magnetic and geometric properties that affect the noise levels are reviewed.