• Title/Summary/Keyword: spin valves

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Modeling of a linear GMR Isolator Utilizing Spin Valves (스핀밸브를 이용한 선형 GMR 아이솔레이터의 모델링)

  • Park, S.;Jo, S.
    • Journal of the Korean Magnetics Society
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    • v.14 no.6
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    • pp.232-235
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    • 2004

  • Linear GMR isolator which is profitable for transmitting analog signal was modeled and the output voltage and current in relation to the input current were investigated. GMR isolator modeling was divided into two parts, namely magnetic and electric parts. The flow chart of the modeling was drawn in which the MR curve of the spin valves were incorporated to obtain the electrical voltage output. For magnetic modeling, 3-dimensional model of planar coil was analyzed by FEM method to obtain the magnetic field strength corresponding to the input current. Coil efficiency of the planar coil having magnetic core layer was shown to have about 1.5 times larger than that of the coil without the magnetic core layer. The feedback coil current(output current) corresponding to the input coil current was calculated to be within ${\pm}$0.25 mA of the linear fitting function of I$\_$out/= I$\_$in/-5 mA. Also, the response time and output waveforms were obtained when the coil current was a rectangular waveform. The rise time and fall time was 6 ${\mu}\textrm{s}$, respectively when the slew rate of the op-amp was 0.3 V/${\mu}\textrm{s}$.

  • https://doi.org/10.4283/JKMS.2004.14.6.232 인용 PDF KSCI

A Possible Origin of Ferromagnetism in Epitaxial BiFeO3 thin Films

  • Chang, Jae-wan;Jang, Hyun M.;Kim, Sang-Koog
    • Journal of Magnetics
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    • v.11 no.3
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    • pp.108-110
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    • 2006

  • We successfully enhanced the performance of a spin valve by inserting an ultra-thin layer of partially oxidized Fe in the pinned and free layers. With the exchange bias field kept large, the spin valve reached a GMR of 12%, which corresponded to a 55% increase in GMR when we compared it with that of spin valves without any inserted layer. The layer of partially oxidized Fe was more effective for improving the properties of the spin valve than the layer of partially oxidized $Co_{90}Fe_{10}$. Considering all the results, we can contribute the significant improvement to the combined effect of the modified local electronic structures at the Fe impurities and theenhanced spin-dependent reflections at the $\alpha-Fe_{2}O_{3} phase in the magnetic layer.

  • https://doi.org/10.4283/JMAG.2006.11.3.108 인용 PDF KSCI

Giant Magnetoresistance Properties of NiO Spin Valves with Naturally Oxidized Free Layer (자연산화된 자유층을 갖는 NiO 스핀밸브 박막의 자기저항특성)

  • 김종기;주호완;이기암;황도근;이상석
    • Journal of the Korean Magnetics Society
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    • v.11 no.3
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    • pp.104-108
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    • 2001

  • The effect of specular electron scattering on natural oxidation of free layer in NiO spin valves have been investigated. The magnetoresistance (MR) ratio and the exchange biasing field ( $H_{ex}$) of NiO(600 $\AA$)Ni$_{81}$$Fe_{19}$(50$\AA$)/Co(7 $\AA$)/Cu(20 $\AA$)/Co(7 $\AA$)Ni$_{81}$$Fe_{19}$(70 $\AA$) spin valves were increased from 4.9 % to 7.3 %, and 110 Oe to 170 Oe after natural oxidation in the atmosphere for 80 days, respectively. The sheet resistivity p decreased from 28$\mu$$\Omega$m to 17$\mu$$\Omega$m, but $\Delta$$\rho$ did not almost change after the oxidation. The spin valves enhanced by the specular electron scattering in the natural]y Co/NiFe/NiFe $O_{x}$ free layer were confirmed from the depth profiles using Auger electron spectroscopy.scopy..

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BOTTOM IrMn-BASED SPIN VALVES BY USING OXYGEN SURFACTANT

  • J. Y. Hwang;Kim, M. Y.;K. I. Jun;J. R. Rhee;Lee, S. S.;D. G. Hwang;S. C. Yu;Lee, S. H.
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.62-63
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    • 2002

  • To reach 100 Gbit/in$^2$ magnetic recording densities in hard disk drives specular enhancement of giant magnetoresistance (GMR) effect in spin valve (SV) films has become one of the indispensable means for application as read elements in recording heads [1]. More recently specular spin valve (SSV) structure containing nano-oxides layers (NOL) were reported [2], where MR enhancement is caused to extended mean free path of majority spin polarized electrons through specular reflection at metal/insulator interfaces [3] in the SV films. (omitted)

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