• 제목/요약/키워드: Spin coupling

검색결과 225건 처리시간 0.032초

Bottom형 IrMn 스핀밸브 박막의 열적안정성과 높은 교환결합력 (Thermal Stability and High Exchange Coupling Field of Bottom Type IrMn-Pinned Spin Valve)

  • 황재연;김미양;이장로
    • 한국자기학회지
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    • 제12권2호
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    • pp.64-67
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    • 2002
  • 속박층 (pinning layer) IrMn를 사용한 Ta/NiFe/IrMn/CoFe/Cu/CoFe/NiFe/Ta 구조의 스핀밸브 박막 (SV; spin valve)을 산화층이 코팅된 Si(111) 기판에 dc 마그네트론 스퍼터링 방법으로 상온에서 제작하였다. 이 SV에 대하여 교환결합자기장 (H$_{ex}$; exchange coupling field), 자기저항 (MR; magnetoresistance)비 및 보자력 (H$_{c}$ coercivity)의 열처리 순환수와 온도 의존성을 조사하였다. 증착조건과 후열처리 조건을 최적화 함으로써 MR비 3.6%, 피속박층의 H$_{ex}$ 11800 Oe을 얻었다. H$_{ex}$는 열처리 순환횟수가 2 이후에 일정한 값을 유지하여 열적으로 안정성을 갖는 것을 확인하였다. H$_{ex}$는 24$0^{\circ}C$ 까지는 600 Oe를 유지하다가 점점 감소하여 27$0^{\circ}C$에 0이 되었다.

위상절연체 소재 및 소자 기술 개발 동향 (Research Trend of Topological Insulator Materials and Devices)

  • 이우정;황태하;조대형;정용덕
    • 전자통신동향분석
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    • 제38권1호
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    • pp.17-25
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    • 2023
  • Topological insulators (TIs) emerge as one of the most fascinating and amazing material in physics and electronics. TIs intrinsically possess both gapless conducting surface and insulating internal properties, instead of being only one property such as conducting, semiconducting, and insulating. The conducting surface state of TIs is the consequence of band inversion induced by strong spin-orbit coupling. Combined with broken inversion symmetry, the surface electronic band structure consists of spin helical Dirac cone, which allows spin of carriers governed by the direction of its momentum, and prohibits backscattering of the carriers. It is called by topological surface states (TSS). In this paper, we investigated the TIs materials and their unique properties and denoted the fabrication method of TIs such as deposition and exfoliation techniques. Since it is hard to observe the TSS, we introduced several specialized analysis tools such as angle-resolved photoemission spectroscopy, spin-momentum locking, and weak antilocalization. Finally, we reviewed the various fields to utilize the unique properties of TIs and summarized research trends of their applications.

DESIGN EVALUATION OF NO SPIN DIFFERENTIAL MODELS USING THE AXIOMATIC APPROACH

  • Pyun, Y.S.;Jang, Y.D.;Cho, I.H.;Park, J.H.;Combs, A.;Lee, Y.C.
    • International Journal of Automotive Technology
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    • 제7권5호
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    • pp.595-601
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    • 2006
  • Two No Spin Differential(NSD) models were benchmarked for a project of Dual-Use Technology. The Axiomatic approach is utilized to evaluate the designs of the models. The Independence Axiom is satisfied at the top level of design but not at the second level, which implies the design exhibits coupling and will admit design improvements. The detailed process of design evaluation is described. It is shown that it is possible to develop a unique and evolutionary NSD design by solving the problems that cause coupling within two models.

The Effects of Deposition Rates on Exchange Coupling and Magnetoresistance in NiO Spin-Valve Films

  • D. G. Hwang;Park, C. M.;Lee, S. S.;Lee, K. A.
    • Journal of Magnetics
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    • 제2권4호
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    • pp.143-146
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    • 1997
  • The effects of deposition rate on exchange coupling field Hex and coercive field Hc in NiO spin-valves are discussed. The Hex and Hc increased with deposition rate of NiO film. The rms roughnesses of the NiO deposited at 6 ${\AA}$/min (NiO-Low) and 30${\AA}$/min (NiO-High) were almost similar, however, the short-range roughness increased with the deposition rate. The Hex, Hc and surface morphologies for the modulated NiO spin-valve films such as NiO-Low\NiO-High\NiO-Low and NiO-High\NiO-Low were investigated.

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[(CoO/NiO)/NiFe/Cu/NiFe] spin-valve 박막에서의 자기저항효과와 자기적 특성에 대한 연구 (The study of magnetoresistance and magnetic properties in [(CoO/NiO)/NiFe/Cu/NiFe] spin-valve thin films)

  • 현준원
    • E2M - 전기 전자와 첨단 소재
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    • 제9권10호
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    • pp.1060-1065
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    • 1996
  • We have studied the magnetoresistance phenomena on spin valve thin films of antiferromagnetic NiO/CoO. Interlayer coupling oscillates between the antiferrocoupling and ferrocoupling with the variation of Cu thickness. The exchange coupling strength between NiO (antiferromagnetic) and NiFe(ferromagnetic) as a function of NiO texture and interface roughness is investigated by CoO insertion. CoO has significantly higher anisotropy in the (111) plane and interface roughness. It seems that the MR-ratio is increased by CoO inserted films. From the AFM and XRD data, the increase of MR-ratio and exchange field is influenced by the roughness of CoO.

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A First-principles Study on Magnetism of Al Impurity in bcc Fe

  • Rahman, Gul;Kim, In-Gee
    • Journal of Magnetics
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    • 제16권1호
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    • pp.1-5
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    • 2011
  • The magnetism and electronic structure of bcc $Al_1Fe_{26}$ was investigated by means of first-principles calculations with and without spin-orbit coupling (SOC). From the calculated total energy, the SOC corrected system is shown to be approximately 5 meV per atom lower than the SOC uncorrected system. The induced spin magnetic moment at the Al site was -0.125 ${\mu}_B$ without SOC and -0.124 ${\mu}_B$ with SOC. The orbital magnetic moments were calculated to be 0.002 ${\mu}_B$ in [$\overline{1}$00] direction for Al. The electronic structures showed the nearest neighbor antiferromagnetic interaction between Fe and Al to be essential for determining the magnetism of the $Al_1Fe_{26}$ system.