Time-Domain Noise Analysis for a Perpendicular Double-Layer Medium.

In perpendicular magnetic recording, medium noise is one of the crucial issues limiting the attainable density. The purpose of the reported work was to find a guiding principle for reducing the medium noise. Although previous work suggested that the media noise is caused by reversed domains in the bit cell, our time-domain noise measurements and a novel model using Voronoi cells suggest another noise origin: a noise source of transition irregularity caused by finite magnetic cluster size.