Modeling and simulation of the writing process on bit-patterned perpendicular media

The recording physics of bit-patterned media is studied for areal densities of around 2 Tbits/inch². A model of the writing process, based on the head field gradient and switching field distribution, including various interference fields, is presented to extract the writehead and media parameters which are necessary to attain a wider write margin. Write head field distributions, calculated by the finite-element method, are presented for various head pole structures with side-and trailing-shields to improve head field gradient. Optimization of the pole configuration increased the gradient to over 500 Oe/nm for a head-to-soft magnetic under layer (SUL) spacing of 14 nm. Using the head field distribution, a recording performance analysis by micromagnetic simulation indicated that the write margin was improved. Position and size dispersions of the dots deteriorated the signal-to-noise ratio (SNR) and increased adjacent track erasure (ATE).