A Physical Model for Predicting Off-Track Capability in Perpendicular Recording

Off-track capability (OTC) after adjacent track squeeze is a critical and independent parameter for determining the track density in hard disk drives. A semi-elliptical equation is derived based on a physical model for the writer pole with an isosceles trapezoid shape. It explains the different behaviors of OTC versus track pitch from both squeeze directions, as well as the variation of OTC versus track pitch due to the change of skew angle. The calculated data of OTC versus track pitch are in good agreement with the experimental data measured from the drive with perpendicular magnetic recording media.