• Title/Summary/Keyword: 자구생성 자기장

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Magnetic Field Dependence of the Activation Volume for Sr-ferrite Particles (Sr-페라이트 자성 입자의 활성화 부피의 자기장 의존성)

  • Kim, Hyeon Soo;Jeong, Soon Young;Kim, Kyung Min;Kwon, Hae-Woong
    • Journal of the Korean Magnetics Society
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    • v.26 no.6
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    • pp.196-200
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    • 2016
  • In this study the mechanisms of magnetization reversal and magnetic interaction effects on activation volumes for Sr-ferrite with different particle sizes are investigated. The activation volumes of C2 sample are larger than those of C3 sample in the range of low magnetic fields. But the fields above the coercivity of sample C2, the activation volumes of both samples are decreased linearly with increasing the applied magnetic field. These phenomena can be explained by the strengths of two critical fields representing the reverse domain nucleation field and the domain wall pinning field as well as the strength of dipolar interaction.

Measurement of Saturation Magnetostriction by the Second-order Higher Harmonics of ac Perturbing Magnetic Field (교류 섭동 자기장의 제 2차 고조파를 이용한 포화자기변헝 측정)

  • Cha, S.Y.;Kim, J.K.;Ryu, K.S.;Cho, Y.R.
    • Journal of the Korean Magnetics Society
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    • v.15 no.2
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    • pp.72-75
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    • 2005
  • The profiles of the second-order higher harmonics during B-H hysteresis loop have been measured as functions of the tensile stress in grain-oriented $3.2{\%}$ Si steels. The observed harmonics profiles have been analyzed in terms of the nonlinear, asymmetric magnetization which reflects the domain reorientation under the field. The field interval of the second-order higher harmonics is related to the nucleation and annihilation fields and a measurement method for the magnetostriction is proposed using the harmonics profiles under tensile stress.

Relation Between Magnetization Easy Axis and Anisotropic Magnetoresistance in Permalloy Films (퍼멀로이 박막의 자화 용이축과 자기저항 변화와의 상관관계에 대한 연구)

  • Hwang, Tae-Jong;Ryu, Yeung-Shik;Kwon, Jin-Hyuk;Kim, Ki-Hyeon;Kim, Dong-Ho
    • Journal of the Korean Magnetics Society
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    • v.18 no.1
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    • pp.28-31
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    • 2008
  • We studied the effect of easy magnetization axis orientation with respect to the strip direction by measuring the magnetoresistance(MR), the magneto-optic Kerr effect(MOKE), and real-time domain evolution. The five strips were patterned on a single chip with the easy axis orientation of each strip relative to the longitudinal direction by around $0^{\circ}$, $18^{\circ}$, $36^{\circ}$, $54^{\circ}$ and $72^{\circ}$, respectively. The overall shape of field dependent MR was mostly governed by the anisotropy magnetoresistnace. The relative change of the longitudinal MR was significantly increased with increasing angle between the easy axis and strip direction, whereas, the transverse MR variation rate was decreased with increasing angle. Several MR steps were observed during the magnetization reversal, and the simultaneous measurement of the MOKE and the domain images identified that the MR steps were associated with evolution of the oppositely directed magnetic domain.

Formation of a Narrow Domain Wall Using Local Exchange Coupled System (국소적 교환상호작용을 이용한 좁은 자벽의 생성)

  • You, Chun-Yeol
    • Journal of the Korean Magnetics Society
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    • v.15 no.4
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    • pp.221-225
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    • 2005
  • Formation of a narrow magnetic domain wall is demonstrated by micromagnetics simulations. It is found that the domain wall width can be shrunk in a local exchange coupled system. The local exchange coupled system means that only a part of a ferromagnetic layer has an exchange coupling with another ferromagnetic layer. The system can be considered as two parts in the lateral dimensions: one is an exchange coupled region and another is a free region. Since the two regions have quite different local switching fields, the domain wall will be formed at the interface between the two regions at moderate field ranges.