Recording Performance of Bit Patterned Media in Account of Magneto-Interaction Field and Bit Error Rate

This study investigates the performance of bit patterned media (BPM) in hard disk drives. It is revealed that written-in errors, rather than traditional signal-to-noise ratio, drive the recording performance of BPM. The staggered BPM structure allows for a larger write pole size, resulting in a larger write field. However, the lateral spacing between adjacent islands in staggered BPM is typically less than conventional BPM, leading to a higher written-in error rate. The investigation determines the effective switching field affected by the magneto-interaction field and finds that the write field is 21% higher in staggered BPM compared to conventional BPM. By analysing the error rate up to areal density of 5 Tb/in2, the study shows that conventional BPM achieves 1 Tb/in2 with the acceptable error rate, while staggered BPM can reach an areal density of 5 Tb/in2 with tight synchronous writing requirements. These insights are useful for designing the structure of BPM in hard disk drives.