Writer pole tip remanence in perpendicular recording

Bai, D.; Zhu, Jian‐Gang; Luo, Peng; Stoev, K.; Liu, F.

doi:10.1109/tmag.2005.862758

Cited by 16 publications

(13 citation statements)

References 21 publications

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“…The geometry of the yoke, pole tip, and coil windings shown in Figure 1(a) is identical to that in Ref. 10. The three coil turns, labeled C1, C2, and C3, lie between the top and bottom layers of the yoke and generate an in-plane driving field when current is applied.…”

mentioning

confidence: 96%

“…Current understanding of yoke dynamics is derived mainly from simulations. 10 In a recent study, 11 time resolved scanning Kerr microscopy (TRSKM) was used to simultaneously detect all three spatial components of the magnetization within a writer structure with a single layer yoke subject to a bias field. Time resolved images confirmed the occurrence of flux beaming, 12 where magnetic flux is concentrated along the symmetry axis of the yoke during dynamic operation of the writer, demonstrating that TRSKM can directly image the dynamic response of the writer.…”

mentioning

confidence: 99%

“…10 The pulse used to excite the writer had 1.6 ns duration and 11.2 V amplitude since larger values led to signals that had noticeable stochastic character. 11,13 The response of the yoke was probed by a laser pulse of 100 fs duration focused onto its surface by a Â 60 microscope objective lens.…”

mentioning

confidence: 99%

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Time resolved scanning Kerr microscopy of hard disk writer structures with a multilayered yoke

Gangmei

Keatley

et al. 2013

Applied Physics Letters

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confidence: 96%

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confidence: 99%

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Time resolved scanning Kerr microscopy of hard disk writer structures with a multilayered yoke

Gangmei

Keatley

et al. 2013

Applied Physics Letters

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“…[1][2][3][4] For a multilayer lamination head, reduction in the net magnetic volume at the pole tip decreases the write field. In the conventional structure, decreasing the aspect ratio of the pole tip and the multilayer lamination have been used to reduce the pole tip remanence.…”

Section: Introductionmentioning

confidence: 99%

Writer pole remanence of a tapered main pole head

Maeda

Kobayashi

Toda

et al. 2010

Journal of Applied Physics

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We used a micromagnetic model to study the head remanence of a perpendicular tapered main pole head. To reduce the head pole tip remanence, a single magnetic domain structure forming a vortex state from the pole tip to the tapered region is preferred. A tapered main pole structure with a trailing gap depth less than about 30 nm and a tapered angle ͑TG͒ equal to about 30°improved the writing efficiency. This was achieved with a head field value more than 1.3 times higher and with a head field gradient about 1.15 times higher than that of the conventional structure. Moreover, the pole tip remanence was reduced to a value closer to that of the conventional structure. The reduction in the throat height had less effect on the reduction in the head remanence in the tapered head than in the conventional head. We also discuss both single pole heads and shielded heads.

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“…This indicates the presence of residual flux propagating through the writer after the driving pulse has ceased, potentially leading to erase-after-write errors in devices of this shape. 17 XPEEM has been used to image the equilibrium state of partially built hard disk write heads, showing detail in the confluence region and pole tip. These images suggest that the crystalline anisotropy dominates the equilibrium state configuration.…”

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confidence: 99%

Imaging the equilibrium state and magnetization dynamics of partially built hard disk write heads

Valkass

Shelford

et al. 2015

Applied Physics Letters

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Four different designs of partially built hard disk write heads with a yoke comprising four repeats of NiFe (1 nm)/CoFe (50 nm) were studied by both x-ray photoemission electron microscopy (XPEEM) and time-resolved scanning Kerr microscopy (TRSKM). These techniques were used to investigate the static equilibrium domain configuration and the magnetodynamic response across the entire structure, respectively. Simulations and previous TRSKM studies have made proposals for the equilibrium domain configuration of similar structures, but no direct observation of the equilibrium state of the writers has yet been made. In this study, static XPEEM images of the equilibrium state of writer structures were acquired using x-ray magnetic circular dichroism as the contrast mechanism. These images suggest that the crystalline anisotropy dominates the equilibrium state domain configuration, but competition with shape anisotropy ultimately determines the stability of the equilibrium state. Dynamic TRSKM images were acquired from nominally identical devices. These images suggest that a longer confluence region may hinder flux conduction from the yoke into the pole tip: the shorter confluence region exhibits clear flux beaming along the symmetry axis, whereas the longer confluence region causes flux to conduct along one edge of the writer. The observed variations in dynamic response agree well with the differences in the equilibrium magnetization configuration visible in the XPEEM images, confirming that minor variations in the geometric design of the writer structure can have significant effects on the process of flux beaming.

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Writer pole tip remanence in perpendicular recording

Cited by 16 publications

References 21 publications

Time resolved scanning Kerr microscopy of hard disk writer structures with a multilayered yoke

Time resolved scanning Kerr microscopy of hard disk writer structures with a multilayered yoke

Writer pole remanence of a tapered main pole head

Imaging the equilibrium state and magnetization dynamics of partially built hard disk write heads

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