Comparisons of standard and modified perpendicular magnetic recording disks with ring head writing

To overcome the superparamagnetic effect in longitudinal magnetic recording (LMR) technology, the combination of perpendicular magnetic recording (PMR) media by writing with an inductive ring head has been suggested as one of the candidates to overwhelm the thermal fluctuation of the recorded magnetization. This has specially attracted attention on its practical application to hard disk drives (HDD), because the conventional LMR head can apply to new PMR disks. In this research, the four types of standard single and double, and modified thin single- and pseudo-double-layered PMR disks are fabricated and evaluated in terms of crystallographic and magnetic properties. Read/write performances of the modified disks by a merged giant magneto resistive (GMR) head show superiority in signal-to-noise ratio (SNR) to those of the standard disks