• 제목/요약/키워드: soft underlayer

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이중층 수직기록 매체에서 read/write 특성에 미치는 soft underlayer의 효과 (Effect of soft underlayer on read/write in double layered perpendicular recording media)

  • 이성철;탁영욱;이택동;이경진
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2002년도 동계연구발표회 논문개요집
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    • pp.180-181
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    • 2002
  • 수직기록매체에서 기록 밀도가 증가하기 위해서는 bit의 크기를 줄여야 하고, 이를 위해서는 writing head의 width와 thickness를 줄여야 한다. 그러나 head의 크기가 줄어들면 기록층의 자화를 반전시키기에 충분한 write field를 얻지 못한다. 이를 극복하기 위해 head의 tip부분을 trimming을 하여 작은 pole tip 크기를 가지면서도 큰 write field를 얻고, 여분의 magnetic field를 얻기 위해 soft underlayer를 도입하는 이중층 수직기록 매체가 제안되고 있다. (중략)

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수직자기기록매체용 Fe-Co-B/M 하지연자성층의 미세결정구조 및 자기특성 (Microstructure and Magnetic Properties in Fe-Co-B/M Films for Soft Magnetic Underlayer of Perpendicular Magnetic Recording Media)

  • 공석현;손인환;금민종;최형욱;박용서;김경환
    • 한국전기전자재료학회논문지
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    • 제17권8호
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    • pp.888-892
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    • 2004
  • It is necessary to develop soft magnetic layer with high saturation magnetization 4 $\pi{M}_s$ and in-plane magnetic anisotropy field Hk for soft magnetic underlayer of perpendicular magnetic recording media with high signal to noise ratio. Fe-Co-B layer with high 4 $\pi$Ms of about 23 kG deposited on Ni-Fe and Ni-Fe/Si seedlayer exhibited very high in-plane magnetic anisotropy filed Hk of about 280 and 380 Oe, respectively, In-plane XRD studies clarified that the lattice spacing of planes along the easy axis direction was longer than that along the hard axis direction in the Fe-Co-B layers with high Hk. These results indicate that high Hk of Fe-Co-B/Ni-Fe and Fe-Co-B/[Ni-Fe/si] layers were resulted from magnetoelastic anisotropy owing to a residual stress. Moreover, the high Hk in the Fe-Co-B/Ni-Fe layer was maintained until 30$0^{\circ}C$ annealing temperature.

Mn-Zn-Fe-O 금속타깃을 이용한 수직자기기록디스크의 하지연자성층용 Mn-Zn ferrite 박막제작 (Preparation for Mn-Zn Ferrite Soft Magnetic Underlayer Perpendicular Magnetic Recording Disk using Mn-Zn-Fe-O Metal Target)

  • 공석현;김경환
    • 한국전기전자재료학회논문지
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    • 제19권9호
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    • pp.883-887
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    • 2006
  • In order to attain high-rate deposition of Mn-Zn ferrite thin film for soft magnetic underlayer in perpendicular magnetic recording media, a reactive sputtering using powder-metal targets under the mixture gas of Ar and $O_{2}$ was performed. It was succeeded that Mn-Zn ferrite films with (111) crystal orientation were deposited on Pt(111) underlayer without any annealing process. The film revealed 3.4 kG of 4 ${\pi}Ms$, 70 Oe of coercivity. The deposition rate of the new method was 16 times as high as that of the conventional method using ferrite target.

Simulation of the Effect of Soft Underlayer Domain Wall Structure on Output Signal in Perpendicular Magnetic Recording

  • Kim, Eun-Sik;Lim, Chee-Kheng;Kim, Yong-Su;Lee, Ju
    • Journal of Magnetics
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    • 제11권2호
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    • pp.83-86
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    • 2006
  • Controlling magnetic domains in soft underlayer (SUL) of perpendicular magnetic recording (PMR) is an important issue for the application of PMR in HDD. We studied the magnetic domain structures in SUL using the finite element based micromagnetic simulation (FEMM) for the SUL models with different thicknesses. The purpose is to simulate the magnetic domain wall noise when the SUL thickness and saturation magnetization are changed. The simulation results show that a 15 nm SUL forms simpler Neel wall domain wall pattern and 40 nm SUL forms complex Bloch wall. To visualize the effect of these domain walls stray field at a read sensor position, the magnetic stray field of the domain walls at air bearing surface (ABS) which is 50 nm above the SUL was simulated and the results imply that Bloch walls have stronger stray field with more complicated field patterns than Neel walls and this becomes a significant noise source. Therefore, the thickness of the SUL should be controlled to avoid the formation of Bloch walls.

패턴드 미디어 채널에서 트랙 위치 오프셋에 따른 성능 (Performance of Read Head Offset on Patterned Media Recording Channel)

  • 김진영;이재진
    • 한국통신학회논문지
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    • 제35권11C호
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    • pp.896-900
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    • 2010
  • 본 논문은 차세대 저장장치로 각광받고 있는 패턴드 미디어 장치에 대한 트랙 위치 오프셋에 따른 성능을 알아본다. 패턴드 미디어 채널은 SUL(Soft Underlayer)의 유무에 따라 1차원 검출기인 비터비 검출기와 2차원 검출기인 2차원 SOVA(Soft output Viterbi algorithm)를 이용해 실험하였고, 트랙 위치 오프셋이 없을 때, 10%, 20%, 30%, 40% 있을 때 실험하였다. 트랙 위치 오프셋이 10%일 때는 성능영화가 0.3 dB ~ 0.5 dB 정도로 크지 않았지만 그 이상이 되면, 성능열화가 심해지는 것을 볼 수 있다.