• Title/Summary/Keyword: [Co/Pd] multilayers

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Magnetization Angle and Thickness Dependence of Perpendicular Exchange Anisotropy in [Pd/Co]n/FeMn Films

  • Choi, S.D.;Joo, H.W.;Yun, D.K.;Lee, M.S.;Lee, K.A.;Lee, H.S.;Kim, S.W.;Lee, S.S.;Hwang, D.G.
    • Journal of Magnetics
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    • v.11 no.2
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    • pp.70-73
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    • 2006
  • The magnetization angle and thickness dependence of magnetic anisotropy in the exchange-biased [Pd/Co]${\times}$5/FeMn multilayers with an out-of-plane anisotropy were investigated to determine the origin of perpendicular exchange biasing. As the Co thickness increased to 1.5 nm in the [Pd(0.8 nm)/Co(t)]${\times}$5/FeMn(120 nm) films, the hysteresis loops were converted from square loops at a thin Co (<0.4 nm) to complicated round ones at a thick Co. The irregularly asymmetric step (IAS) at the left top of the loop appeared in the loop of the 0.6-nm Co film due to an inhomogeneity in the exchange anisotropy. As the Pd thickness increased to 1.6 nm, the step disappeared, and the perpendicular magnetic anisotropy was maximized in the Co thickness between 0.6 and 0.9 nm. The conversion of the magnetization loop along the magnetization angle coincided with the equation $H_{(eff)}=H_o\;cos{\theta}$. The IAS of the 0.8-nm Pd film disappeared after thermal annealing up to $200^{\circ}C$ under an external magnetic field.

Coersivity Alteration of Free Layer in the [Co/Pd] Spin-valves with Perpendicular Magnetic Anisotropy ([Pd/Co] 다층박막을 이용한 수직스핀밸브 구조에서 비자성층에 인접한 강자성 물질과 그 두께에 따른 자유층의 보자력 변화)

  • Heo, Jang;Choi, Hyong-Rok;Lee, Ky-Am
    • Journal of the Korean Magnetics Society
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    • v.20 no.3
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    • pp.89-93
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    • 2010
  • We study the giant magneto-resistance (GMR), coercivity and their dependence on the ferromagnetic layers adjacent to the nonmagnetic layer in a spin-valve structure, [Pd/ferromagnetic] multilayers with perpendicular anisotropy. We fabricated a basic spinvalve structure of $[Pd/Co]_2$/ferro-magnetic layer/nonmagnet/ferro-magnetic layer/$[Pd/Co]_2$/FeMn and investigated the dependence of its GMR and magnetic properties such ad coercivity on the ferromagnetic material to reduce the coercivity of the free layer. We try to reduce the freelayer coercivity by controlled the anisotropy, we insert the material NiFe, $Co_8Fe_2$, $Co_9Fe_1$ to ferromagnetic layers adjacent to the Cu layer. Then, we have been able to reduce the coercivity as low as 100 Oe, and also achieved 6.7% of magneto-resistance ratio when the ferromagnetic layer thickness was 0,7 nm.

Exchange Bias Perpendicular Magnetic Anisotropy by Buffer Layer and Inserted Layer in [Pd/Co]5/FeMn Multilayer ([Pd/Co]5/FeMn 막에서의 바닥층과 삽입층에 의한 교환바이어스수직자기이방성)

  • Joo, Ho-Wan;An, Jin-Hee;Lee, Mi-Sun;Kim, Bo-Keun;Choi, Sang-Dea;Lee, Kee-Am
    • Journal of the Korean Magnetics Society
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    • v.14 no.5
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    • pp.192-195
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    • 2004
  • Magnetic properties by exchange biased perpendicular magnetic anisotropy in [Pd(0.8 nm)/Co(0.8 nm)]$_{5}$/FeMn(15 nm) multilayers deposited by dc magnetron sputtering system are investigated. As inserted Pd layer of interface between [Pd/Co] multilayer and FeMn film, the Hex of perpendicular anisotropy was improved from 127 Oe to 145 Oe. But result of an experiment by thermal stability, the Hex of the case that an inserted layer was inserted in decreased from low 20$0^{\circ}C$ in about 5$0^{\circ}C$ more if not inserted. If Ta was a buffer layer, the experiment results along material of buffer layer, the H$_{ex}$ obtained the largest 127 Oe. And if Pd was a buffer layer, H$_{ex}$ obtained the largest 169 Oe. Also, the Hc in buffer layer of Ta and Pd obtained the largest 203 Oe and 453 Oe, respectively.

Local Laser Annealing in Exchange-Biased Films with Out-of-Plane and In-Plane Magnetic Anisotropy

  • Choi, S.D.;Kim, S.W.;Jin, D.H.;Yun, D.K.;Lee, M.S.;Ahn, J.H.;Joo, H.W.;Lee, K.A.;Lee, S.S.;Hwang, D.G.
    • Journal of Magnetics
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    • v.11 no.2
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    • pp.66-69
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    • 2006
  • Local magnetization reversal in the exchange-biased NiFe/FeMn and $[Pd/Co]_5/FeMn$ multilayers with in-plane and out-of-plane magnetic anisotropy was achieved by using laser annealing. The local annealed NiFe/FeMn film under the opposite magnetic field shows a magnetoresistance (MR) curve having two symmetric peaks at the positive and negative exchange biasing field (${\pm}H_{ex}$). The intensity of the nucleated MR peak rises as the exposed area extends during the laser annealing process, and the peak disappears under the reverse magnetic field. In the case of [Pd/Co]/FeMn films, the local magnetization reversal increased gradually as the laser power increases. The locally reversed magnetization was restored under the opposite magnetic field.

INTERLAYER COUPLING AND MAGNETOOPTICS IN MULTILAYERS

  • Lu, M.;Bie, Q.S.;Xu, Y.B.;Zhai, H.R.;Zhou, S.M.;Chen, Liangyao;Jin, Q.Y.
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.561-566
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    • 1995
  • Additional magnetooptical Kerr effect (AMOKE) was observed in several multilayer structures. For Fe/Pd and Co/Cu Multilayers, AMOKE enhanced the Kerr rotation in short wavelength side, while for Fe/Ag and FeSi/Cu multilayer systems the Kerr rotation enhancement appeared in long wavelength side. A number of ferromagnetic/nonmagnetic/ferromagnetic(FM/NM/FM) sandwiches showed that the AMOKE led to oscillations of Kerr rotation and Kerr ellipticity in certain wavelength range with changing NM layer thickness similar to the oscillatory interlayer coupling. The oscillation of effective optical constants related to the MOKE oscillation was observed for the first time. The mechanisms of the AMOKE were discussed.

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