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

Suess, Dieter; Fuger, Markus; Abert, Claas; Bruckner, Florian; Vogler, Christoph

doi:10.1038/srep27048

Cited by 3 publications

(2 citation statements)

References 36 publications

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“…The minimum value of T f differs based on the saturation magnetization of the SM part. This dependence of the coercivity on the intergranular exchange is well known in the case of thin exchange-coupled structures [44][45][46].…”

Section: B Origin Of Jitter Reductionmentioning

confidence: 54%

Noise Reduction Based on an Fe−Rh Interlayer in Exchange-Coupled Heat-Assisted Recording Media

et al. 2017

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High storage density and high data rate are two of the most desired properties of modern hard disk drives. Heat-assisted magnetic recording (HAMR) is believed to achieve both. Recording media, consisting of exchange-coupled grains with a high and a low T C part, were shown to have low dc noise-but increased ac noise-compared to hard magnetic single-phase grains like FePt. We extensively investigate the influence of an Fe-Rh interlayer on the magnetic noise in exchange-coupled grains. We find an optimal grain design that reduces the jitter in the down-track direction by up to 30% and in the off-track direction by up to 50%, depending on the head velocity, compared to the same structures without FeRh. Furthermore, the mechanisms causing this jitter reduction are demonstrated. Additionally, we show that, for short heat pulses and low write temperatures, the switching-time distribution of the analyzed grain structure is reduced by a factor of 4 compared to the same structure without an Fe-Rh layer. This feature could be interesting for HAMR use with a pulsed laser spot and could encourage discussion of this HAMR technique.

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Section: B Origin Of Jitter Reductionmentioning

confidence: 54%

Noise Reduction Based on an Fe−Rh Interlayer in Exchange-Coupled Heat-Assisted Recording Media

et al. 2017

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“…The minimum value of T f differs based on the saturation magnetization of the SM part. This dependence of the coercivity on the intergranular exchange is well known for thin exchange spring structures [39][40][41].…”

Section: B Origin Of Jitter Reductionmentioning

confidence: 55%

AC noise reduction based on exchange coupled grains for heat-assisted-magnetic recording: The effect of an FeRh interlayer

Vogler,

Abert,

Bruckner

et al. 2017

Preprint

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High storage density and high data rate are two of the most desired properties of modern hard disk drives. Heat-assisted magnetic recording (HAMR) is believed to achieve both. Recording media, consisting of exchange coupled grains with a high and a low TC part, were shown to have low DC noise, but increased AC noise, compared to hard magnetic single phase grains, like FePt [1]. In this work we extensively investigate the influence of an FeRh interlayer on the magnetic noise in exchange coupled grains. We find an optimal grain design that reduces the jitter in down-track direction by up to 30 % and in off-track direction by up to 50 %, depending on the head velocity, compared to the same structures without FeRh. Further, the mechanisms causing this jitter reduction are demonstrated. Additionally, we show that for ultrashort heat pulses and low write temperatures the switching time distribution of the analyzed grain structure is reduced by a factor of four, compared to the same structure without FeRh layer. This feature could be interesting for HAMR with a pulsed laser spot and could resume the discussion about this HAMR technique.

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

Vogler

Abert

Bruckner

et al. 2016

Journal of Applied Physics

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Heat-assisted-magnetic recording (HAMR) is hoped to be the future recording technique for high density storage devices. Nevertheless, there exist several realizations strategies. With a coarsegrained Landau-Lifshitz-Bloch (LLB) model we investigate in detail benefits and disadvantages of continuous and pulsed laser spot recording of shingled and conventional bit-patterned media. Additionally we compare single phase grains and bits having a bilayer structure with graded Curie temperature, consisting of a hard magnetic layer with high TC and a soft magnetic one with low TC, respectively. To describe the whole write process as realistic as possible a distribution of the grain sizes and Curie temperatures, a displacement jitter of the head and the bit positions are considered. For all these cases we calculate bit error rates of various grain patterns, temperatures and write head positions to optimize the achievable areal storage density. Within our analysis shingled HAMR with a continuous laser pulse moving over the medium reaches the best results, and thus having the highest potential to become the next generation storage device.

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

Cited by 3 publications

References 36 publications

Noise Reduction Based on an Fe−Rh Interlayer in Exchange-Coupled Heat-Assisted Recording Media

Noise Reduction Based on an Fe−Rh Interlayer in Exchange-Coupled Heat-Assisted Recording Media

AC noise reduction based on exchange coupled grains for heat-assisted-magnetic recording: The effect of an FeRh interlayer

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

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