• Title/Summary/Keyword: magnetization switching

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Magnetic Force Microscopy (MFM) Study of Remagnetization Effects in Patterned Ferromagnetic Nanodots

  • Chang, Joon-Yeon;Fraerman A. A.;Han, Suk-Hee;Kim, Hi-Jung;Gusev S. A.;Mironov V. L.
    • Journal of Magnetics
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    • v.10 no.2
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    • pp.58-62
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    • 2005
  • Periodic magnetic nanodot arrays were successfully produced on glass substrates by interference laser lithography and electron beam lithography methods. Magnetic force microscopy (MFM) observation was carried out on fabricated nanodot arrays. MFM tip induced magnetization effects were clearly observed in ferromagnetic elliptical nanodots varying in material and aspect ratio. Fe-Cr dots with a high aspect ratio show reversible switching of the single domain magnetization state. At the same time, Co nanomagnets with a low aspect ratio exhibit tip induced transitions between the single domain and the vortex state of magnetization. The simple nanolithography is potentially an efficient method for fabrication of patterned magnetic arrays.

A Model of Magnetic Bearings Considering Eddy Currents and Hysteresis

  • Myounggyu Noh
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.3
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    • pp.5-11
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    • 2003
  • A simulation model for radial magnetic bearings is presented. The model incorporates hysteresis, saturation and eddy current effects. A simple magnetization model that describes hysteresis and saturation is proposed. Eddy currents are taken into consideration by assuming that they are generated by single-turn fictitious coils wrapped around each magnetic flux path. The dynamic equations describing the simulation model can easily incorporate the operation of switching power amplifier. A simulation of a typical 8-pole radial magnetic bearing produces switching waveforms very similar to the experimental observation.

Investigation on the Free Layer Switching behavior of a Spin-valve MTJ Device with 2 Dimensional Magnetic Field (2차원 자기장에 의한 spin-valve 터널링 자기저항 소자의 자유층 반전 거동에 관한 연구)

  • Lee, Young-Woo;Kim, Cheol-Gi;Kim, Chong-Oh
    • Korean Journal of Materials Research
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    • v.13 no.6
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    • pp.394-397
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    • 2003
  • MTJ devices are fabricated using metal shadow masks and switching characteristics are investigated under 2 dimensional magnetic field. When the hard axis field is less than $\pm$ 16 Oe, switching behavior is similar to that based on the Stoner-Wohlfarth model. As the hard axis field is larger than $\pm$ 16 Oe, deviation from the expectation by Stoner-Wohlfarth model is observed. These phenomena are induced by the generation of multi-domain and inhomogeneous magnetization reversal.

Effect of NiO spin switching on the Fe film magnetic anisotropy in epitaxially grown Fe/NiO/Ag(001) and Fe/NiO/MgO(001) systems

  • Kim, Won-Dong;Park, Ju-Sang;Hwang, Chan-Yong;Wu, J.;Qiu, Z.Q.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.366-366
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    • 2010
  • Single crystalline Fe/NiO bilayers were epitaxially grown on Ag(001) and on MgO(001), and investigated by Low Energy Electron Diffraction (LEED), Magneto-Optic Kerr Effect (MOKE), and X-ray Magnetic Linear Dichorism (XMLD). We find that while the Fe film has an in-plane magnetization in both Fe/NiO/Ag(001) and Fe/NiO/MgO(001) systems, the NiO spins switch from out-of-plane direction in Fe/NiO/MgO(001) to in-plane direction in Fe/NiO/Ag(001). These two different NiO spin orientations generate remarkable different effects that the NiO induced magnetic anisotropy in the Fe film is much greater in Fe/NiO/Ag(001) than in Fe/NiO/MgO(001). XMLD measurement shows that the much greater magnetic anisotropy in Fe/NiO/Ag(001) is due to a 90o-coupling between the in-plane NiO spins and the in-plane Fe spins which causes a switching of the NiO spins during the Fe magnetization reversal.

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