• Title/Summary/Keyword: 수직 자기 이방성

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Dependence of Coercivity and Exchange Bias as Surface Magnetic Anisotropy in [Pd/Ferromagnet] Multilayer with Out-of-plane Magnetic Anisotropy (수직자기이방성을 갖는 [Pd/Ferromagnet] 다층막에서 표면자기이방성에 따른 교환력과 보자력의 의존성)

  • Heo, Jang;Kim, Hyun-Shin;Choi, Jin-Hyup;Lee, Ky-Am
    • Journal of the Korean Magnetics Society
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    • v.18 no.3
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    • pp.98-102
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    • 2008
  • Dependence of the exchange bias and coercivity as surface magnetic anisotropy and ferromagnet materials for $[Pd/Co]_N$ and $[Pd/Co,(CoFe)]_N$/FeMn multilayers with perpendicular magnetic anisotropy were investigated. The coercivity was proportionally increased to 670 Oe by increasing stack number N in Ta(2.1 nm)/[Pd(3.1/N)/$Co(1.2/N)]_N$/Ta(2.1) multilayers with perpendicular magnetic anisotropy. Also, the coercivity in exchange biased multilayer was tend to increased by increasing stack number N. But coercivity of each materials have been in order of Co (600 Oe), $Co_5Fe_5$ (520 Oe) and $Co_8Fe_2$ (320 Oe) as function of the ferromagnet materials. The other side, exchange force of each materials is 300 Oe when the reiteration layer number N is 3. In over number of reiteration layer 3, they maintained coercivity between 200 Oe and 300 Oe.

First Principle Studies on Magnetism and Electronic Structure of Perovskite Structured CoFeX3 (X = O, F, S, Cl) (페로브스카이트 구조를 가지는 CoFeX3(X = O, F, S, Cl) 합금의 자성과 전자구조에 대한 제일원리계산)

  • Jekal, Soyoung;Hong, Soon Cheol
    • Journal of the Korean Magnetics Society
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    • v.26 no.6
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    • pp.179-184
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    • 2016
  • For an industrial spin-transfer torque (STT) MRAM, low switching current and high thermal stability are required, simultaneously. For this point of view, it is essential to find magnetic materials which satisfy high spin polarization and strong perpendicular magnetocrystalline anisotropy (MCA). In this paper, we investigate electronic structures and MCA energies of perovskite $CoFeX_3$ (X = O, F, S, Cl). For X = F and Cl, spin polarization at the Fermi level are 97 % and 96 %, respectively, which are close to a half metal. Furthermore, Co-terminated 5-monolayer (ML) $CoFeX_3$ (X = O, F, S, Cl) films show perpendicular MCA. In particular, the MCA energy of the Co-terminated $CoFeCl_3$ is about 1.0 meV/cell which is three times larger than that of a 5-ML CoFe film. Therefore, we expect to realize a magnetic material with high spin polarization and strong perpendicular MCA energy by utilizing group 6 and 7 elements in the periodic table, and to contribute to commercializing of the STT-MRAM.

A Study on the Magnetic Anisotrpy and Magnetoresistive Characteristics of NiFe/Cu/Co Trilayers (NiFe/Cu/Co 삼층막의 자기이방성과 자기저항 특성에 관한 연구)

  • 김형준;이병일;주승기
    • Journal of the Korean Magnetics Society
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    • v.6 no.5
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    • pp.323-328
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    • 1996
  • NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers were formed on the $4^{\circ}$ tilt-cut Si(111) substrate by rf magnetron sputtering method. With a Cu($50\;{\AA}$) underlayer, NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers developed in-plane magnebc anisotropy and in-plane perpendicular alignment of easy axes in two magnetic components of NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers has been found. The easy axis of Co layer consisbng of NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers turned out to be along $4^{\circ}$ tilt Si <112> direcbon and that of NiFe layer along Si <110> direction. [NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$)]/Cu($50\;{\AA}$)/Si(111, $4^{\circ}$ tiIt-cut) trilayers showed about 2.2 % MR ratio at room temperature and large plateau in MR curves, which are more improved MR characteristics than those in [NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$)]/Cu($50\;{\AA}$)/glass trilayers with no appreciable magnetic anisotropy.

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