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Author: search.filters.author.Tipcharoen, W.

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    Composite media with reduced write temperature for heat assisted magnetic recording
    (2019-09-15)
    Natekar, N. A.
    ;
    Tipcharoen, W.
    ;
    Victora, R. H.
    A major issue plaguing Heat Assisted Magnetic Recording (HAMR)is the high writing (T<inf>write</inf>)and peak heat spot temperatures (T<inf>peak</inf>). To counter this, a low temperature thermal exchange coupled composite (ECC)media with reduced write temperature relative to previous high temperature thermal ECC media is introduced. The FePt T<inf>c</inf> is reduced from 700 K to 500 K, and the write layer T<inf>c</inf> is reduced from 900 K to 600 K. Optimizations for M<inf>s</inf> and K<inf>u</inf> of the write layer generate values of M<inf>s</inf> = 700 emu/cm<sup>3</sup> and K<inf>u</inf> = 1.0 × 10<sup>7</sup> erg/cm<sup>3</sup> at 300 K. Switching Probability Distribution (SPD)calculations with lowered T<inf>peak</inf> = 650 K indicate T<inf>write</inf> = 487 K. This indicates a T<inf>write</inf> reduction by 34% as compared to the previous write temperature of 738 K for the high temperature thermal ECC media. Examining the FWHM of the SPD under 0% and 3% T<inf>c</inf> variation indicates a noise reduction of ∼20% relative to single layer high T<inf>c</inf> FePt media, and a much larger reduction relative to low T<inf>c</inf> FePt media. The jitter values at lowered T<inf>c</inf> approach the ideal value set by the grain size in the absence of any T<inf>c</inf> and K<inf>u</inf> variation. Simulations with uncorrelated and correlated T<inf>c</inf> and K<inf>u</inf> variations in the write and FePt layer generate similar results. Reduction of FePt T<inf>c</inf> may reduce the anisotropy relative to its undoped value: reduction of anisotropy by 33% is found to adversely affect the SPD by only 3–4%, but has a larger impact on jitter. These results help establish the usefulness of a low temperature thermal exchange coupled composite media for HAMR.
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    Investigation of writing error in staggered heated-dot magnetic recording systems
    (2017-05-01)
    Tipcharoen, W.
    ;
    Warisarn, C.
    ;
    Tongsomporn, D.
    ;
    Karns, D.
    ;
    Kovintavewat, P.
    To achieve an ultra-high storage capacity, heated-dot magnetic recording (HDMR) has been proposed, which heats a bit-patterned medium before recording data. Generally, an error during the HDMR writing process comes from several sources; however, we only investigate the effects of staggered island arrangement, island size fluctuation caused by imperfect fabrication, and main pole position fluctuation. Simulation results demonstrate that a writing error can be minimized by using a staggered array (hexagonal lattice) instead of a square array. Under the effect of main pole position fluctuation, the writing error is higher than the system without main pole position fluctuation. Finally, we found that the error percentage can drop below 10% when the island size is 8.5 nm and the standard deviation of the island size is 1 nm in the absence of main pole jitter.