SNR and density limit estimates: a comparison of longitudinal and perpendicular recording

Bertram, H.N.; Williams, M. L.

doi:10.1109/20.824417

Cited by 236 publications

(90 citation statements)

References 22 publications

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“…One of the key requirements is a large ratio of coercivity and magnetization, which in SI units should be about three [2]. Another requirement is a large nucleation field |H n | and optimum shearing of the hysteresis such that the slope at the coercivity is mainly limited by demagnetization: α=4πdM/dH| Hc ≅ 1 [3].…”

Section: Introductionmentioning

confidence: 99%

Growth, structural, and magnetic properties of high coercivity Co/Pt multilayers

Weller

Folks

Best

et al. 2001

Journal of Applied Physics

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Co/Pt multilayer films ([Co (t Co nm)/Pt(1 nm)] 10 , 0.2 250 o C show fine-grained MFM features on the sub-100 nm length scale and hysteresis studies indicate reversal dominated by localized switching of small clusters. The hysteresis curves for the highest coercivity films are sheared with with a hysteresis slope α=4πdM/dH|Hc≅1.5, which is close to the ideal value for completely decoupled grains of α =1. High resolution cross-sectional TEM with elemental analysis shows columnar grains extending throughout the multilayer stack. Sharp Co/Pt interfaces are found from TEM and grazing incidence X-ray diffraction. At higher T G , Co depletion and structural defects at the grain boundaries provide a mechanism for exchange decoupling of adjacent grains, which may result in the high coercivities observed. Anisotropy and magnetization values are estimated as K u ~ 8x10 6 erg/cc and M S ~ 450 emu/cc (per total volume), hence H k = 2K u /M S ~ 17.5 kOe for the highest coercivity H c ~ 15 kOe films.

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Section: Introductionmentioning

confidence: 99%

Growth, structural, and magnetic properties of high coercivity Co/Pt multilayers

Weller

Folks

Best

et al. 2001

Journal of Applied Physics

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“…If the technology of hybrid recording emerges into products, it is fairly certain that the magnetic medium will exhibit perpendicular anisotropy, since the advantages of vertical recording are reasonably well established for future high areal density recording [7]. Media for hybrid recording presents additional challenges and opportunities beyond conventional perpendicular media.…”

Section: Medium Materials Developmentmentioning

confidence: 99%

“…If optical means are used to impart heating, then optical reflectance and absorbance of the medium surface must be designed to insure efficient energy transfer from the heating transducer to the disk. On the other hand, hybrid recording may allow the media designer to avoid use of the often onerous "soft underlayer" that appears essential for perpendicular media [7], or if necessary, have it also function as a heat sink. In hybrid recording, most of the writability assistance is provided by heat, and a conventional inductive ring writer may provide vertical fields of adequate quality with heated media.…”

Section: Medium Materials Developmentmentioning

confidence: 99%

Materials Development for Thermally-Assisted Magnetic Recording Media

Brucker

McDaniel

2001

MRS Proc.

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We have carried out a combined experimental and computer simulation study to specify and identify candidate films to support high areal density, thermally-assisted magnetic recording. The motivation of this work is to utilize the enhanced writability of very high coercivity materials that thermal assistance can provide. Media with high coercivity (and anisotropy Ku) are known to be essential to achieve a sufficiently high ratio of KuV/kBT necessary to maintain magnetic stability at temperature T in media switching units (grains; single domains) of volume V. Nominally, we expect V ∝ D−3/2, where D is the medium bit density per unit area in recording. A micromagnetic recording simulation tool with a capability of representing realistic grain size distributions, temperature-dependent magnetic properties, and spatially-varying imposed temperature distributions was employed to study the interplay of thermal and magnetic field gradients in the recording process. In addition, a simple LLG-based thermomagnetic switching model supplemented the micromagnetics model. We fabricated improved Co/X multilayer media for recording evaluation, and performed standard materials characterization.

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“…However, only in-plane magnetization has been demonstrated up-to-date in these magnetic patterning methods. Notably, for many applications ͑e.g., magnetic recording͒, 16 outof-plane magnetization would be favorable.…”

mentioning

confidence: 99%

Out-of-plane magnetic patterning on austenitic stainless steels using plasma nitriding

Menéndez

Stinville

Tromas

et al. 2010

Applied Physics Letters

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A correlation between the grain orientation and the out-of-plane magnetic properties of nitrogen-enriched polycrystalline austenitic stainless steel surface is performed. Due to the competition between the magnetocrystalline anisotropy, the exchange and dipolar interactions, and the residual stresses induced by nitriding, the resulting effective magnetic easy-axis can lay along unusual directions. It is also demonstrated that, by choosing an appropriate stainless steel texturing, arrays of ferromagnetic structures with out-of-plane magnetization, embedded in a paramagnetic matrix, can be produced by local plasma nitriding through shadow masks.

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SNR and density limit estimates: a comparison of longitudinal and perpendicular recording

Cited by 236 publications

References 22 publications

Growth, structural, and magnetic properties of high coercivity Co/Pt multilayers

Growth, structural, and magnetic properties of high coercivity Co/Pt multilayers

Materials Development for Thermally-Assisted Magnetic Recording Media

Out-of-plane magnetic patterning on austenitic stainless steels using plasma nitriding

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