Skew angle effects on disk recording performance at high recording densities

Skew angle effects on the transition noise are analyzed in the longitudinal disk media by micromagnetic simulations at area densities from 14.3 Gb/in( 2) to 31.5 Gb/in(2). The transition noise, including the peak, width and ji tter noise, is the dominant noise in ultra-high density disk recording syst ems. An isotropic medium and an oriented medium, with a fixed grain size of 135 Angstrom and a coercivity of 2900 Oe, are chosen for the noise analysi s. The peak noise is studied by the distribution of the peak magnetization amplitude M-p in each bit. The transition a-parameter is no longer the valu e as given in the William-Comstock approximation. It is found that the tran sition noise is highly dependent on both the linear density and the skew an gle, where the bit length and the grain size are on the same order. In both media, the medium noise increases severely when the skew angle is above 10 degrees.