DC modulation noise in clustered particulate media

Parker, D.A.; Kay, G.E.; Bissell, P.R.; Mercer, Tim

doi:10.1016/s0304-8853(01)01161-1

Cited by 3 publications

(3 citation statements)

References 9 publications

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“…2, a trend can be seen at the lower frequencies where an overall increase in noise is observed with decreasing media thickness. Previous experimental [2] and modeling [4] studies have shown that large associations (e.g. clusters of magnetic particles formed in the wet stages of the manufacturing process) result in noise maxima in both of the magnetically saturated states.…”

Section: Resultsmentioning

confidence: 99%

Effects of structure on noise in very thin particulate data storage media

Mercer¹,

Bissell²,

Tatarasanu³

2007

Journal of Magnetism and Magnetic Materials

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A c c e p t e d m a n u s c r i p tEffects of structure on noise in very thin particulate data storage media AbstractThe effects of structure on noise in very thin particulate data storage tapes have been investigated using DC and tone-noise methods. The results from a set of five commercial development tapes indicate that large structural correlations of size ~ 5 µm become increasingly apparent as the magnetic layer of the tapes becomes thinner over the range 140 -50 nm. As the samples were fabricated from identical particles (MP4 -length ~ 60nm) using the same double coating process, and with the tone-noise results showing comparable top surface roughness, these findings are consistent with large in-plane structures at the magnetic/non-magnetic interface that may be expected from mixing effects during production drying. Since this interface moves ever closer to the head with increasing data density, its effects on media noise will become increasingly important.

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Section: Resultsmentioning

confidence: 99%

Effects of structure on noise in very thin particulate data storage media

Mercer¹,

Bissell²,

Tatarasanu³

2007

Journal of Magnetism and Magnetic Materials

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“…This yields an interesting contrast with the peak-like observations of McCann et al, 11 in which an electromagnet ͑equivalent very large gap write head͒ was used to ensure a uniform applied field in the plane of the tape. Additionally, a more recent modeling study of Parker et al, 5 that extends the statistically uncorrelated model of Mallinson 13 by introducing clusters, has shown that the introduction of correlations between particle moments can convert peak-like to trough-like behavior.…”

Section: Introductionmentioning

confidence: 99%

“…For example, at time of writing the linear tape-open ͑LTO͒ and super digital linear tape technologies already offer ϳ100 Gbytes of storage on a cartridge, with the areal density of the first generation LTO tape being quoted as 100 Mbits/square inch. 2 Although these advanced formats have only become commercially available quite recently, academic interest is already evident [3][4][5][6][7][8] and, with roadmaps clearly defined for at least three further generations, is set to continue.…”

Section: Introductionmentioning

confidence: 99%

Effects of magnetic layer thickness and of head-to-medium spacing on noise in advanced particulate recording media

Mercer

Bissell

Ardeleanu

et al. 2003

Journal of Applied Physics

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Effects of magnetic layer thickness on noise in advanced double-layer metal particle tape Recording performance of the combination of magnetoresistive head and thin metal evaporated tapeThe effects of magnetic layer thickness on the noise characteristics of advanced metal particle tape have been observed using a dc demagnetization process generated with a uniform in-plane magnetizer. The three-dimensional ͑3D͒ surface maps of spectral noise power plotted as a function of remanent magnetization state showed a change in behavior as the recording layer became thinner. The thickest magnetic coating of 310 nm showed ''trough-like'' characteristics associated with conventional thick particulate media. The thinnest sample with a 165 nm magnetic coating showed a ''peak-like'' response that is observed in continuous thin-film media, with a graduated trend from one to the other for the two intermediate samples. A simulation of these results has been made with an 8000 spherical particle micromagnetic model of the media remanent states and a simulated magnetoresistive read head. Noise maps produced from the simulation compared well with experiment. Spatial isolation of the noise contributions was achieved by dividing the modeled magnetic layer into sublayers. This revealed that particles at the surface were the source of the ''peak-like'' response, and their contributions became more dominant as the magnetic coating got thinner. Further model investigations showed an association of the different sublayer characteristics with a change in the mean magnetostatic interaction field. The interaction field of particles at the surface had characteristics similar to those of 2D granular thin films and hence generated ''thin film-like'' noise. A further effect was associated with the spacing between the head and various regions of particles. As this was increased, not only was the amplitude of the noise reduced, but the increased region of integration meant that longer range correlations were incorporated into the observed characteristics, resulting in noise maps more like those of conventional thick particulate media.

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