High density recording with keepered media and planar heads

Coughlin, Tom; Hoinville, J. R.; Gooch, B.; Haines, William G.; Payne, A. P.

doi:10.1063/1.364852

Cited by 8 publications

(8 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They found that the pulse sharpening of keepered recording observed by Gooch, et aI., can be accompanied by time-shifts and time asymmetries. Work by Coughlin et al [19,20] also revealed asymmetric pulse amplitude. These nonlinearities are apparently caused by the relatively large fields produced in the keeper layer by the recorded transition, Figure 2.…”

Section: Read Processmentioning

confidence: 88%

“…Off the sides of the head, however, the reluctance of the intervening air gap and the shunting effect of the keeper cause the fields to drop more rapidly than normal. Measurements of trackprofiles reveal a reduction in write-width of 5% [20). More significantly, the side erase-bands [24] have been measured to drop by a factor of two (see section VII B).…”

Section: B Off-track Effectsmentioning

confidence: 93%

See 1 more Smart Citation

Keepered Media Recording: super-resolution for magnetic recording

Wood

Coughlin²,

Monson

1997

J. Magn. Soc. Jpn.

View full text Add to dashboard Cite

Keepered media are made up of two layers: a conventional hard longitudinal film plus a soft magnetic film or "keeper" layer. To recover the written data, a small DC bias current is applied to the inductive readback head. The nonlinear behavior of the soft film in the presence of the bias field provides the mechanism for super-resolution. This paper reviews the history and principles of keepered recording. The structure and fabrication of keepered media are described. Measurements are presented which show the improved resolution and amplitude and which quantify the noise, non linearity, and sidereadingisidewriting behavior. Several other "keepered" configurations including perpendicular options are described. Work is ongoing to optimize the performance of keepered media with MR heads. There is also evidence that the keeper stabilizes the stored data and will extend the superparamagnetic limit on areal recording density

show abstract

Section: Read Processmentioning

confidence: 88%

Section: B Off-track Effectsmentioning

confidence: 93%

Keepered Media Recording: super-resolution for magnetic recording

Wood

Coughlin²,

Monson

1997

J. Magn. Soc. Jpn.

View full text Add to dashboard Cite

show abstract

“…Before undertaking IRM curve measurements, the samples were demagnetized using the DC cyclic erasure process (DCE) [5]. This is done by taking M-H loops at gradually reduced values of maximum field.…”

Section: Methodsmentioning

confidence: 99%

“…However, we have previously studied traditional longitudinal media with a soft underlayer, i.e., so-called "keepered media" [5]. These films had a CoCrPt recording layer with a NiFe underlayer.…”

Section: Effect Of a Soft Underlayer On Coupling In Longitudinal Fmentioning

confidence: 99%

Magnetic characterization of perpendicular recording media

Holloway

Laidler

et al. 2002

IEEE Trans. Magn.

View full text Add to dashboard Cite

Article:Wu, J. orcid.org/0000-0003-0007-4328, O'Grady, K., Khizroev, S. et ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract-In this paper, we describe techniques for the magnetic characterization of perpendicular recording media. Such measurements made using traditional techniques, such as the vibrating sample magnetometry (VSM) and alternating gradient force magnetometer (AGFM), have to be corrected for the sample shape demagnetizing factor, which is often found not to be equal to 4 . For measurements other than the simple hysteresis loop, such as remanence curves, this correction must be carried out in real time and we describe the method by which this can be achieved and the process for achieving the correct demagnetization of perpendicular films prior to measurements of the isothermal remanent magnetization curve. A further complication is that real perpendicular media have a soft underlayer beneath the recording layer, which swamps and confuses signals from instruments such as VSM or AGFM. Hence, we describe the construction and use of a magnetooptical Kerr effect magnetometer, which does not penetrate significantly into the soft layer and enables the perpendicular layer to be measured independently. We describe the properties of a traditional alloy perpendicular medium and a Co-Pd multilayer system, which in the latter case exhibits multiple switching behavior. We also address the issue of the effect of the soft underlayer on the coupling in similar longitudinal films and find that the presence of the underlayer induces significant additional coupling effects that may well give rise to an increase in noise in recorded signals.

show abstract

“…In the quest for increasing the areal densities of rigid and flexible magnetic recording media, a keepered magnetic recording media was proposed (Loven, 1994; Coughlin, 1996, 1997; Reed, 1996; Wood, 1997). It was made essentially by adding a thin layer of soft‐magnetic material (keeper layer) above (or under) the hard‐magnetic storage layer.…”

Section: Introductionmentioning

confidence: 99%

Design optimization of a non‐linear magnetic media system using finite element analysis and Taguchi method

Chen

Low

Leow

2002

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

View full text Add to dashboard Cite

This paper reports an application of the combined FEM analysis and Taguchi's DOE method to the parameter optimization of a magnetic recording media. Effects of a soft magnetic keeper layer on the performance of the magnetic recording media disk are analysed using FEM. Optimization of several key parameters using Taguchi method is performed to maximise the desirable characteristics which are brought about by this keeper layer. This application example shows that the combined approach is an effective and efficient tool for parameter optimization of a non‐linear magnetic field system.

show abstract

High density recording with keepered media and planar heads

Cited by 8 publications

References 7 publications

Keepered Media Recording: super-resolution for magnetic recording

Keepered Media Recording: super-resolution for magnetic recording

Magnetic characterization of perpendicular recording media

Design optimization of a non‐linear magnetic media system using finite element analysis and Taguchi method

Contact Info

Product

Resources

About