Three-dimensional modeling of perpendicular reading with a soft underlayer

Roscamp, T.; Boerner, E.D.; Parker, Geoffrey

doi:10.1063/1.1452281

Cited by 22 publications

(16 citation statements)

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“…For the pulse response , we have adopted the well-known Lorentzian approximation [26] for longitudinal recording, i.e., where is the pulsewidth at half the maximum amplitude. For perpendicular recording systems, we adopt the approximation [27], [28] ( 2) where we have introduced the error function and defined the parameter as the pulsewidth at half the maximum amplitude of . We define the parameter as the normalized density.…”

Section: Channel Modelmentioning

confidence: 99%

Multidimensional signal processing and detection for storage systems with data-dependent transition noise

Pighi

Raheli

Amadei³

2006

IEEE Trans. Magn.

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In the last decade, significant research on detection algorithms capable of mitigating the effects of colored Gaussian thermal noise and transition noise in storage systems, has been performed. In this paper, we present a new detection scheme based on a multidimensional detector front end and multidimensional linear prediction, applied to maximum a posteriori probability (MAP) sequence detection. This method improves the bit-error-rate (BER) performance with respect to previous approaches and makes the detector quite insensitive to transition noise. We show that the gain in terms of BER versus signal-to-noise ratio with our detector increases with the user density. The results obtained for a magnetic storage channel are extendable to optical storage systems as well.Index Terms-Longitudinal and perpendicular recording, magnetic storage systems, multidimensional linear prediction, multidimensional signal processing, optical storage systems, transition noise.

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Section: Channel Modelmentioning

confidence: 99%

Multidimensional signal processing and detection for storage systems with data-dependent transition noise

Pighi

Raheli

Amadei³

2006

IEEE Trans. Magn.

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“…The dipped profile of the ring head is likely due to the weak write field at the media, and the greater ease of writing at the track edge than at track center, a result of weaker demag fields (of the media) and higher effective fields (from the writer) at the track edges. We do not think the dip is a readback effect since it is not observed with the FIBed heads having the same GMR readers [7]. Presumably, the field at the media from the FIBed heads is large enough that it can readily switch the grains across the trackwidth, resulting in the desired flat profile.…”

Section: Resultsmentioning

confidence: 96%

FIB Micro-Machined Perpendicular Writers for Media Characterization

et al. 2004

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A focused ion beam (FIB) is used to fabricate singlepole perpendicular writers by micro-machining longitudinal (ring) heads at the HGA. The heads are designed for media characterization, and a comparison is made between the performance of the FIBed and ring heads on perpendicular media. The FIBed heads write much more effectively, approximately 7 dB gain in the signal-to-noise ratio (SNR), and efficiently than their ring-head counterparts. In addition, the FIBed heads generate very reliable (small scatter) thermal decay rates for the evaluated disks whereas the unFIBed ring heads cannot, all of which make them more suitable for characterization of perpendicular media. Our results further demonstrate the value and versatility of FIB-machining as a research tool to design and fabricate novel recording heads with robust performance.Index Terms-Disk drives, focused ion beam, magnetic heads, magnetic recording, system analysis and design.

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“…The medium also includes a log-normal distribution of the crystalline anisotropy field magnitude and a Gaussian distribution for its orientation. The written transition pattern is read back using a read sensitivity function in conjunction with a reciprocity based read process [15]. Monte-Carlo simulation of 100 isolated transitions is done to calculate the variation in transition position or transition jitter.…”

Section: Writability and Thermal Erase Width Considerationsmentioning

confidence: 99%

Investigations of Perpendicular Write Head Design for 1>tex<$hboxTb/in^2$>/tex<

et al. 2004

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We have revisited the considerations of perpendicular recording at 1 Tb/in 2 . We have extensively modeled head designs with the down-track shield (DS) and head designs with the down-track and side shields (DS-SS). The side shields are needed to reduce the thermal erase width, however, there is a substantial reduction in effective write field for the DS-SS heads compared to the DS heads. This reduction in effective write field defines an upper limit for the anisotropy of the medium that can be written. As a consequence, it is hard to simultaneously achieve writability and the thermal stability requirement for 1 Tb/in 2 .Index Terms-Bit-aspect ratio (BAR), effective write field, finite-element model (FEM), micromagnetic model, neighborhood induced transition shift (NITS), perpendicular recording, side shields, signal-to-noise ratio (SNR), soft underlayer (SUL), Tb/in 2 , thermal erase width, transition jitter, transition shift, writability, write width.

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Three-dimensional modeling of perpendicular reading with a soft underlayer

Abstract: Articles you may be interested inCoCrPt-oxide based perpendicular recording media with hybrid soft magnetic underlayers J. Appl. Phys.

Cited by 22 publications

References 2 publications

Multidimensional signal processing and detection for storage systems with data-dependent transition noise

Multidimensional signal processing and detection for storage systems with data-dependent transition noise

FIB Micro-Machined Perpendicular Writers for Media Characterization

Investigations of Perpendicular Write Head Design for 1>tex<$hboxTb/in^2$>/tex<

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Three-dimensional modeling of perpendicular reading with a soft underlayer

Abstract: Articles you may be interested inCoCrPt-oxide based perpendicular recording media with hybrid soft magnetic underlayers J. Appl. Phys.

Cited by 22 publications

References 2 publications

Multidimensional signal processing and detection for storage systems with data-dependent transition noise

Multidimensional signal processing and detection for storage systems with data-dependent transition noise

FIB Micro-Machined Perpendicular Writers for Media Characterization

Investigations of Perpendicular Write Head Design for 1&gt;tex&lt;$hboxTb/in^2$&gt;/tex&lt;

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Investigations of Perpendicular Write Head Design for 1>tex<$hboxTb/in^2$>/tex<