Chun Lian Ong; Shiming Ang; Zhejie Liu; Zhimin Yuan, "Additional Reader Noise in TDMR Reader for ITI Cancelation," in Magnetics, IEEE Transactions on , vol.50, no.11, pp.1-4, Nov. 2014 doi: 10.1109/TMAG.2014.2317782
Shingled writing eliminates the writer width limitation and enables further bit aspect ratio reduction to extend the areal density growth of current perpendicular magnetic recording. The achievable track density of shingled magnetic recording (SMR) is determined by the reader width rather than the writer width. However, continuously scaling of reader width increases the reader resistance and results in higher reader noise. It would be an issue to maintain enough signal to noise ratio of reader. Two dimensional magnetic recording (TDMR) was proposed to extend the density growth by advanced signal processing technique. In TDMR configuration, there are multiple readers to read multiple tracks simultaneously. Recently, the TDMR reader was proposed as a solution of inter-track interference (ITI) cancellation, which allows to use wider reader to reproduce signals from narrow tracks. In this work, an additional reader noise is observed when the reader was positioned to read 2 tracks at the same time. The formation of the reader sensor appears to be closely related to the current reader structure with Hard Bias Magnet. This issue highlights that a solution is required to enable TDMR, probably a reader structure without Hard-Biased.
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