Abstract
Servo signals can be written with incredibly high speed compared to conventional methods, high accuracy and low cost by using a magnetic printing method. There are two types of magnetic printing for perpendicular hard disks. One is bit printing where printing magnetic field is applied in perpendicular direction, and the other is edge printing where the field is applied in in-plane direction. The merit of the bit printing is that the reproduced waveform from printed hard disks is almost the same as that from head-recorded ones. On the other hand, in the edge printing high S/N is expected in short bit length region. It is possible to magnetic-print the bit below 50nm long, which shows the perpendicular magnetic printing is usable for ultrahigh density hard disks such as 1Tb/in^2 or more.
