• Title/Summary/Keyword: Spin coupling

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Magneto resistance in NiO/NiFe/Cu/NiFe spin-valve Sandwiches (NiO/NiFe/Cu/NiFe 스핀-밸브 샌드위치의 자기저항 특성)

  • 김재욱
    • Electrical & Electronic Materials
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    • v.10 no.10
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    • pp.1016-1021
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    • 1997
  • Magneto resistance properties in spin-valve sandwiches with various thickness of nanmagnetic layer in contact with the ferromagnetic NiFe film were investigated. The NiFe layer in contact with the NiO film was pinned by strongly exchange-biased coupling and the free NiFe layer at the film surface induced a sharp change in the magnetoresistance at -5~15Oe due to small coercivity. The NiO/NiFe/Cu/NiFe film showed a magnetoresistance ratio in the range of 2.3~2.9% and a field sensitivity above 2.2%/Oe with various of nonmagnetic layer. The NiO/NiFe/Cu/NiFe film of the field sensitivity above 2.2%/Oe suggests stang possibility of magnetic sensor matter.

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The Structure, and the Magnetic and Magnetoresistive Characteristics of the Spin Valve Multilayers

  • Stobiecki, T.;Czapkiewicz, M.;Wrona, J.;Powroynik, W.;Stobiecki, F.
    • Journal of Magnetics
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    • v.3 no.3
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    • pp.92-95
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    • 1998
  • In this paper we report the low and high angle diffraction results, and the magnetic and magnetroesistive characteristics of the spin valve multilayer structure prepared by the sputter machine Emerald II in the Balzers Laboratory. The investigated system consists of a ferromagnetic free layer (7 nm NiFe) and a ferromagnetic pinned layer (7 nm NiFe), separated from each other by a nonmagnetic (2.1 nm Cu) spacer. The NiFe pinned layer is fixed by the exchange coupling with an antiferromagnetic layer (10 nm FeMn). For such system the magnetoresistance ratio ΔR/R=3.58%, the interlayer exchange coupling $H_c=6.4$ Oe and the field sensitivity 1.15%/Oe were otained.

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Optical Properties of $I^B-AI-VI^B_2$$I^B-AI-VI^B_2 :Co^{2+}$ Crystals ($I^B-AI-VI^B_2$$I^B-AI-VI^B_2 :Co^{2+}$결정의 광학적 특성연구)

  • 김화택;김창대;윤창선;진문석;최성휴
    • Journal of the Korean Vacuum Society
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    • v.4 no.3
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    • pp.334-341
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    • 1995
  • IB-AI-VIB2 및 IB-AI-VIB2 :Co2+ 결정을 고순도 원소를 출발 물질로 하고 iodine을 수송 매체로 사용하여 chemical transport reaction method로 성장시켰다. 성장된 결정의 결정구조는 chalcopyrite 구조였으며, energy gap은 direct band gap으로 3.514~1.814 eV 정도로 주어졌으며, cobalt를 불순물로 첨가할 때 energy gap은 감소하였다. IB-AI-VIB2 :Co2+ 결정에서 첨가된 cobalt가 모체결정의 Td symmetry site에 Co2+ ion으로 위치하여, Co2+ ion의 energy 준위 사이의 전자전이에 기인하는 불순물 광흡수 peaks가 나타났다. 이 불순물 광흡수 peaks에 결정장 이론을 적용하여 구산 1st-order spin-orbit coupling parameter(λ)는 -183~ -189cm-1정도였고, 2nd-order spin-orbit coupling parameter(P)는 225~239 cm-1정도였으며, crystal field parameter(Dq)는 328~395cm-1, Racah parameter(B)는 531~552cm-1정도였다.

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Electron Spin Resonance Study on the Miscibility of Poly(ethylene glycol) with Cathonic Dodecyl Trimethylammonium Bromide Micelle

  • Kim Jin-Soo;Lee Don-Keun;Kang Young-Soo
    • Journal of the Korean Magnetic Resonance Society
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    • v.9 no.2
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    • pp.155-162
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    • 2005
  • The interaction of poly(ethylene glycol)(PEG) with cationic dodecyl trimethyl ammonium bromide (DTAB)micelle was studied with electron spin resonance (ESR) by determining line widths of the ESR spectra and coupling constant of nitrogen($A_N$). The degree of ESR line shape change such as line widths and coupling constant indicated that PEG mixes well with DTAB micelle due to a great hydrophobic interaction with surfactant alkyl chains. This suggests that the PEG can be used as non-ionic surfactant to disperse the exposed oil in the ocean.

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Electron Spin Resonance Study on the Miscibility of Poly(ethylene glycol) with Cationic Dodecyl Trimethylammonium Bromide Micelle

  • Kim, Jin-Soo;Shin, Dong-Ran;Kang, Young-Soo
    • Journal of the Korean Magnetic Resonance Society
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    • v.1 no.1
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    • pp.59-70
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    • 1997
  • The interaction of poly(ethylene glycol) (PEG) with cationic dodecyl trimethyl ammonium bromide (DTAB) micelle was studied with electron spin resonance (ESR) by determining line widths of ESR spectra and coupling constant of nitrogen(AN). The degree of ESR line shape change such as line widths and coupling constant indicated that PEG mixes well with DTAB micelle due to a great hydrophobic interaction with surfactant alkyl chains. This suggests that the PEG can be used as non-ionic surfactant to disperse the exposed oil in the ocean.

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Magnetism in α-RuCl3 : Dependence on Coulomb Interaction and Hund's Coupling

  • Gong, Hoshin;Kim, Kyoo;Ji, Sungdae;Kim, Bongjae;Min, B.I.
    • Journal of the Korean Physical Society
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    • v.73 no.11
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    • pp.1691-1697
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    • 2018
  • Employing the density functional theory, we have investigated the roles of Coulomb and Hund's interactions in the electronic and magnetic properties of newly discovered ${\alpha}-RuCl_3$ having the $R{\overline{3}}$ symmetry, which is in close proximity of the Kitaev system. We show that both the size and the direction of local magnetic moment are highly dependent on Coulomb and Hund's interactions, and the spin and orbital parts show different behaviors. The validity of the so-called $j^{eff}$ picture is accessed upon interaction parameters, and the explicit roles of Hund's interaction in the local electronic structures and magnetic properties are discussed.

Exchange and Interlayer Coupling in NiO Spin Valve Films (NiO 스핀밸브 박막에서 교환결합과 사잇층 결합에 관한 연구)

  • 박창만;고성호;황도근;이상석;이기암
    • Journal of the Korean Magnetics Society
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    • v.7 no.5
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    • pp.258-264
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    • 1997
  • Exchange and interlayer couplings between a NiFe ferromagnetic layer and an antiferromagnetic NiO layer in NiO/NiFe/Cu/NiFe spin-valve films prepared by rf/dc magnetron sputtering were investigated. The interlayer coupling field ($H_{int}$ decreased with the Cu layer thickness, and the exchange coupling field $(H_{ex}$ saturated to 90 Oe. the magnetitudes of $H_{ex}$ and $H_{int}$ decreased with increasing thickness of the pinned NiFe layer. The increase of $H_{int}$ with the free NiFe layer may be due to the increased magnetization.

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