Jitter measurements in magnetic recording

Transition jitter in magnetic storage can be caused by a variety of factors such as contributions by the medium, head, underlying magnetization, and drive electronics. Medium jitter is attributed to the magnetic microstructure. As the storage density increases, transition noise and medium jitter effects increase significantly and could be potential limiting factors for storage density in the disk drive design. A technique to study medium jitter measurements using in situ methods has been developed. This technique relies on high-resolution measurements developed for in situ imaging. The average positional jitter measurement down-track is repeatable. The measured jitter was about 3.2-6.5 nm on a track with write width about 0.375 μm. The cross correlation between the positional jitter mappings from two different recording frequencies shows a strong peak, demonstrating that the jitter maps are independent of the recording frequency and dependent on the medium microstructure.