Areal density optimizations for heat-assisted magnetic recording of high-density media

Vogler, Christoph; Abert, Claas; Bruckner, Florian; Suess, Dieter; Praetorius, Dirk

doi:10.1063/1.4953390

Cited by 24 publications

(27 citation statements)

References 25 publications

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“…This material configuration can be seen in Figure 1(a) and was already studied in former works. [9][10][11] Secondly, a grain consisting of two identical layers FePt is considered where the only difference is the peak temperature of the applied heat pulse. Hereby, the peak temperature of the heat pulse applied to the top layer is assumed to be 20% larger than that applied to the bottom layer (see Figure 1(b)).…”

Section: A Variation Of T Peakmentioning

confidence: 99%

Curie temperature modulated structure to improve the performance in heat-assisted magnetic recording

Muthsam¹,

Vogler²,

Suess³

2019

Journal of Magnetism and Magnetic Materials

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We investigate how a temperature reduction in z−direction influences the switching probability and the noise in heat-assisted magnetic recording (HAMR) for a bit in bit-patterned media with dimensions d = 5 nm and h = 10 nm. Pure hard magnetic bits are considered and simulations with a continuous laser pulse are performed using the atomistic simulation tool VAMPIRE. The results display that the switching behavior shows a thermally induced exchange spring effect. Simultaneously, both the AC and the DC noise increase. Additionally, we illustrate how an artificial Curie temperature gradient within the material can compensate the HAMR performance loss due to the temperature gradient. Further, due to the graded Curie temperature, DC noise can be reduced compared to a structure where no temperature gradient is considered.

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Section: A Variation Of T Peakmentioning

confidence: 99%

Curie temperature modulated structure to improve the performance in heat-assisted magnetic recording

Muthsam¹,

Vogler²,

Suess³

2019

Journal of Magnetism and Magnetic Materials

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“…29. It has to be noted that in heat assisted recording besides the transition jitter which leads to AC noise also thermally written in errors are a serious problem that lead to DC error129.…”

Section: Implication Of Switching Field Distribution For Bit-patternementioning

confidence: 99%

Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media

Suess

Fuger

Abert

et al. 2016

Sci Rep

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We report two effects that lead to a significant reduction of the switching field distribution in exchange spring media. The first effect relies on a subtle mechanism of the interplay between exchange coupling between soft and hard layers and anisotropy that allows significant reduction of the switching field distribution in exchange spring media. This effect reduces the switching field distribution by about 30% compared to single-phase media. A second effect is that due to the improved thermal stability of exchange spring media over single-phase media, the jitter due to thermal fluctuation is significantly smaller for exchange spring media than for single-phase media. The influence of this overall improved switching field distribution on the transition jitter in granular recording and the bit error rate in bit-patterned magnetic recording is discussed. The transition jitter in granular recording for a distribution of Khard values of 3% in the hard layer, taking into account thermal fluctuations during recording, is estimated to be a = 0.78 nm, which is similar to the best reported calculated jitter in optimized heat-assisted recording media.

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“…DC noise restricts the maximum switching probability of grains away from the transition. It has been shown, that pure hard magnetic grains do not switch reliably [13] if bit-patterned media are considered whereas non-optimized exchange coupled bilayer structures [14][15][16][17][18][19] of hard and soft magnetic material experience high AC noise [20]. A work to reduce noise in recording media by optimizing a high/low T c bilayer structure (see Ref.…”

Section: Introductionmentioning

confidence: 99%

Improving the signal-to-noise ratio for heat-assisted magnetic recording by optimizing a high/low Tc bilayer structure

Muthsam

Slanovc

Vogler

et al. 2019

Journal of Applied Physics

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We optimize the recording medium for heat-assisted magnetic recording by using a high/low T c bilayer structure to reduce AC and DC noise. Compared to a former work, small Gilbert damping α = 0.02 is considered for the FePt like hard magnetic material. Atomistic simulations are performed for a cylindrical recording grain with diameter d = 5 nm and height h = 8 nm. Different soft magnetic material compositions are tested and the amount of hard and soft magnetic material is optimized. The results show that for a soft magnetic material with α SM = 0.1 and J ij,SM = 7.72 × 10 −21 J/link a composition with 50% hard and 50% soft magnetic material leads to the best results. Additionally, we analyse how much the areal density can be improved by using the optimized bilayer structure compared to the pure hard magnetic recording material. It turns out that the optimized bilayer design allows an areal density that is 1 Tb/in 2 higher than that of the pure hard magnetic material while obtaining the same SNR. arXiv:1907.05027v1 [physics.app-ph]

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Areal density optimizations for heat-assisted magnetic recording of high-density media

Cited by 24 publications

References 25 publications

Curie temperature modulated structure to improve the performance in heat-assisted magnetic recording

Curie temperature modulated structure to improve the performance in heat-assisted magnetic recording

Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media

Improving the signal-to-noise ratio for heat-assisted magnetic recording by optimizing a high/low Tc bilayer structure

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