Magnetic Cluster Size Distribution and Its Relation to Read/Write Performance From Spinstand Testing

Hashimoto, Mitsuhiro; Nakagawa, Hiroyuki; Nakamoto, K.; Ide, H.; Ichihara, Takayuki

doi:10.1109/tmag.2009.2022335

Cited by 11 publications

(8 citation statements)

References 12 publications

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“…The auto-correlation method described in this paper used a scanning probe magnetic imaging technique, in contrast to the approach of Hashimoto et al [5] who employed the spinstand noise readback signal to derive the auto-correlation functions. Although the down-track resolution of nowadays reader sensors is comparable with the HRMFM resolution, readers lack the cross-track resolution needed for an accurate 2-D mapping of the magnetic domain structure of ac-erased media.…”

Section: Discussionmentioning

confidence: 99%

“…However, the noise spectrum recorded in a spinstand setup contains valuable information about the cluster size distribution. Another difference between our approach and the Hashimoto method [5] is the cluster size definition. In our analysis, we found a better correlation with the FWHM of auto-correlation function than the zero-crossing.…”

Section: Discussionmentioning

confidence: 99%

“…A large cluster negatively impacts the writing process by making the transition parameter [2] wider and the playback process by decreasing the number of independent microtracks [3] in the cross-track direction. Thus, cluster size and size distribution determine the jitter [4], [5] and translate directly into the signal-to-noise ratio (SNR) [6]- [8] of high-density recording systems in which the jitter is the dominant noise mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Direct Measurement of the Magnetic Cluster Size Using High-Resolution Magnetic Force Microscopy

2015

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High-resolution magnetic force microscopy was used to image high linear density tracks and measure the magnetic cluster size of the ac-erased state of perpendicular magnetic recording media. The full-width at half-maximum (FWHM) of the auto-correlation function corresponding to an ac-erased region determines the correlation length, i.e., the magnetic cluster size. This is demonstrated by comparing the calculated FWHM of auto-correlation function obtained on simulated Voronoi granular structures with the expected value for magnetically decoupled grains. The cluster size we obtained using the auto-correlation procedure is about four grain sizes. The impact of the finite cluster size on the recording performance was assessed by following the trend of tracks' auto-correlation function with increasing the linear density.Index Terms-Magnetic cluster size, magnetic force microscopy (MFM), magnetic recording.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct Measurement of the Magnetic Cluster Size Using High-Resolution Magnetic Force Microscopy

2015

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“…The lateral exchange field in the model was used to control cluster size. The cluster size is estimated by auto-correlation of AC erased media noise [3]. The AC erase was done by writing a tone pattern of 5 nm bit length.…”

Section: B Cluster Sizementioning

confidence: 99%

“…For example, although smaller transition width media is expected to show both low noise power and its increase according to linear density more linearly, such low noise media show clear saturation at lower linear density. And such noise saturation phenomena seem to depend on cluster size [3]. To understand the intrinsic performance of recording media correctly, media noise power saturation phenomena should be understood more exactly.…”

Section: Introductionmentioning

confidence: 99%

A Study of Linear Density Dependence of Media Noise Power in Perpendicular Magnetic Recording

Nishida¹,

Katada²,

Hashimoto³

et al. 2013

IEEE Trans. Magn.

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Media noise power saturates at high linear density in perpendicular magnetic recording. It has been reported that one of the root causes is transition noise saturation due to unsaturated magnetization governed by transition width. However, noise saturation phenomena cannot be fully explained by this mechanism alone. For example, low noise media which saturate at lower linear density show better read-write performance. In this study, we show that noise saturation can be explained by a combination of a readback effect and a noise spectrum that changes with density.

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Characterization of magnetic clustering and its effect on switching behavior and recording performance in perpendicular media

Jung

Ghaderi

Shi

2011

Journal of Applied Physics

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Characterization of magnetic clustering and its effect on magnetic switching behavior and recording performance are investigated. Intergranular exchange coupling constant (Jc) of full-stack media is controlled over a wide range by applying a bias voltage (VB) to the bottom oxide layer only while the other conditions remain the same. With increasing VB up to 300 V, Hn considerably increases by 25% while Hc and Hs remain constant. Magnetic correlation length (Dn) extracted from major and minor loops is plotted with Jc values estimated from the ΔH(M,ΔM) method. Two distinct regions emerge, with lower Jc and larger Dn at VB ≤ 200 V, and with higher Jc and much larger Dn at VB > 200 V. These regions are consistent with the microstructures of biased CoCrPt-SiO2 films reported elsewhere. An increase in the intrinsic switching field distribution is also observed at VB > 200 V. Good correlation between KuV/kT and Dn2, and the increase in coherent switching behavior for media with higher VB, can be understood by the magnetic clustering effect. All the recording parameters of OW, resolution, low-frequency amplitude, magnetic core width, and SNR correlate well with Dn.

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Magnetic Cluster Size Distribution and Its Relation to Read/Write Performance From Spinstand Testing

Cited by 11 publications

References 12 publications

Direct Measurement of the Magnetic Cluster Size Using High-Resolution Magnetic Force Microscopy

Direct Measurement of the Magnetic Cluster Size Using High-Resolution Magnetic Force Microscopy

A Study of Linear Density Dependence of Media Noise Power in Perpendicular Magnetic Recording

Characterization of magnetic clustering and its effect on switching behavior and recording performance in perpendicular media

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