Head/Media Integration Challenge Toward 1 ${\hbox{Tb/in}}^{2}$ Perpendicular Recording

Katada, H.; Hashimoto, Mitsuhiro; Urakami, Y.; Das, Sarbanoo; Shiimoto, M.; Sugiyama, M.; Ichihara, Takayuki; Hoshiya, H.; Tanahashi, Kôtarô; Nakamoto, K.

doi:10.1109/tmag.2010.2040248

Cited by 12 publications

(3 citation statements)

References 23 publications

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“…Furthermore, these intermediate field angles are of crucial relevance in magnetic recording as the key technological application of PMA films. 29,30 Therefore, we have studied the angle-dependent magnetization reversal for epitaxial Co (0001) samples with PMA in the present work.…”

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confidence: 99%

Field angle dependent change of the magnetization reversal mode in epitaxial Co (0001) films

et al. 2014

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confidence: 99%

Field angle dependent change of the magnetization reversal mode in epitaxial Co (0001) films

et al. 2014

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“…Perpendicular magnetic recording (PMR) is approaching its areal density (AD) limit at around 1 Tb/in 2 [1]. Shingled writing [2] is able to maintain the write ability on PMR media and further extend the AD growth of PMR.…”

Section: Introductionmentioning

confidence: 99%

Signal Processing for Dedicated Servo Recording System

Cai

Chan

et al. 2015

IEEE Trans. Magn.

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Perpendicular magnetic recording (PMR) in the hard disk drive is approaching its physical limits. In an earlier work, the dedicated servo recording system has been proposed to provide continuous position error signal (PES) for servo, enable higher servo sampling rate and improve the overall servo performance. A further benefit is that the dedicated servo layer results in surface area savings at the data layer. However, it was also reported that the embedded servo layer introduces baseline variation and non-linear transition shifts to the readback signal of the data layer. In this work, we propose novel signal processing techniques to improve the bit error rate (BER) in dedicated servo recording. The synchronous averaging technique is proposed to improve the BER in the presence of baseline variation distortions. Further, the servo and data-dependent noise prediction (SDDNP) method is proposed to mitigate the effect of the non-linear transition shift. Through the use of these techniques the linear density loss from conventional PMR media is reduced.

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“…T HE perpendicular magnetic recording (PMR) is approaching its areal density (AD) limit at around 1 Tb/in 2 [1]. The shingled writing [2] is able to maintain the write ability on PMR media and further extends the AD growth of PMR.…”

Section: Introductionmentioning

confidence: 99%

Dedicated Servo Recording System and Performance Evaluation

et al. 2015

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The perpendicular magnetic recording (PMR) in hard disk drives is approaching its physical limitation. The emerging technologies, such as heat assisted magnetic recording and microwave assisted magnetic recording have been proposed to record on magnetic media with thermally stable smaller size grains at higher areal density (AD). However, in the media fabrication, achieving wellisolated small size of grains is more challenging than obtaining high K u material as recording media. Reducing the number of grains per bit is a major path for keeping AD growth of PMR in recent years. To minimize the SNR penalty at a smaller grain number per bit, pushing more on track density is the right approach. With the 2-D magnetic recording (TDMR) readers for inter-track interference cancellation, the off-track read capability is improved significantly for allowing a narrower track read. In the drive working environment, when the external vibration or other mechanical disturbance happens during the writing process, it creates more track squeeze at adjacent tracks and leaves a very narrow track at some locations of the track. When the track width is narrower than the squeeze to death width in the 747 curve, it causes hard failure in the channel. To solve the track squeeze problem, this paper proposes to add an additional magnetic recording layer in between the data recording layer and the soft underlayer of conventional PMR media. This additional recording layer is used to record servo information only. The continuous positioning error signal is able to improve the servo performance and to provide the real-time monitoring of the positioning error. When it is under bad servo conditions, the writing process can be stopped to avoid nontolerable track squeeze. The continuous servo signals are designed to be of moderate intensity at very low frequency, and its impact on data signal has been minimized. The linear density gap between the dedicated servo media and the conventional PMR media is able to be controlled within 3%. As the dedicated servo system keeps only around 100 wedges of track ID and sector ID at the data layer, the surface area saving at the data layer can break even in capacity. The dedicated servo technology together with TDMR readers is the key technology to achieve ultrahigh track density during both writing and reading processes.Index Terms-Continuous position error signal (PES), dedicated servo, dedicated servo media, perpendicular magnetic recording (PMR), servo control.

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Head/Media Integration Challenge Toward 1 ${\hbox{Tb/in}}^{2}$ Perpendicular Recording

Cited by 12 publications

References 23 publications

Field angle dependent change of the magnetization reversal mode in epitaxial Co (0001) films

Field angle dependent change of the magnetization reversal mode in epitaxial Co (0001) films

Signal Processing for Dedicated Servo Recording System

Dedicated Servo Recording System and Performance Evaluation

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