• Title/Summary/Keyword: antiferromagnet

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Attempt Frequency of Magnetization in Synthetic Antiferromagnet (인위적 반강자성체에서 자화의 시도주파수)

  • Sur, Hong-Ju;Lee, Kyung-Jin
    • Journal of the Korean Magnetics Society
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    • v.19 no.1
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    • pp.1-4
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    • 2009

  • Solving the stochastic Landau-Lifshitz-Gilbert equation numerically, we investigate the attempt frequency of magnetization in synthetic antiferromagnet (SyAF). The attempt frequency is estimated while varying the uniaxial anisotropy constant, the energy barrier and the geometry of a magnetic layer. It is found that the attempt frequency is decreased for the same magnetic volume by increasing the asymmetry of the geometry in the high damping region. Also, even for a constant height of energy barrier, the attempt frequency can vary dramatically with uniaxial anisotropy constant.

  • https://doi.org/10.4283/JKMS.2009.19.1.001 인용 PDF KSCI

Phonon-Assisted Electron Hopping Conduction in the Uranium Doped One-Dimensional Antiferromagnet Ca2CuO3

  • Thanh, Phung Quoc;Yu, Seong-Cho;Nhat, Hoang-Nam
    • Journal of Magnetics
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    • v.13 no.4
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    • pp.132-135
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    • 2008

  • The authors studied the conduction mechanism in an uranium doped low dimensional magnetic system $Ca_2CuO_3$. This system exhibits the S=1/2 quasi 1D antiferromagnetic chains of -Cu-O- with strong magnetic coupling, and demonstrates continuous semiconductor-like behavior with constant covalent insulator character. This paper identifies the conduction is due to thermally activated phonon-assisted electron hopping between dopant uranium sites. The parameter a, the characteristic for hopping probability, was determined to be 0.18 ${\AA}^{-1}$. This value manifests a relatively stronger hopping probability for $Ca_2CuO_3$ as compared with other uranium doped ceramics.

  • https://doi.org/10.4283/JMAG.2008.13.4.132 인용 PDF KSCI

Exchange Bias Coupling Depending on Uniaxial Deposition Field of Antiferromagnetic FeMn Layer

  • Lee, Sang-Suk;Hwang, Do-Guwn
    • Journal of Magnetics
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    • v.15 no.1
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    • pp.17-20
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    • 2010

  • The relationship between ferromagnet anisotropic magnetization and the antiferromagnet atomic spin configuration was investigated for various angles of the uniaxial deposition magnetic field of the FeMn layer in the Corning glass/Ta(5nm)/NiFe(7nm)/FeMn(25nm)/Ta(5nm) multilayer that was prepared by the ion beam sputter deposition. The exchange bias field ($H_{ex}$) obtained from the measurement of the easy-axis MR loop decreased to 40 Oe at the deposition field angle of $45^{\circ}$, and to 0 Oe at the angle of $90^{\circ}$. When the difference between the uniaxial axis between the ferromagnet NiFe and the antiferromagnet FeMn was $90^{\circ}$, the strong antiferromagnetic dipole moment of FeMn caused the weak ferromagnetic dipole moment of NiFe to rotate in the interface.

  • https://doi.org/10.4283/JMAG.2010.15.1.017 인용 PDF KSCI

Universal time relaxation behavior of the exchange bias in ferromagnetic/antiferromagnetic bilayers

  • Dho Joonghoe
    • Proceedings of the Korean Magnestics Society Conference
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    • 2005.12a
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    • pp.80-81
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    • 2005

  • The resilience of the exchange bias ($H_{EX}$) in ferromagnet / antiferromagnet bilayers is generally studied in terms of repeated hysteresis loop cycling or by protracted annealing under reversed field (training and long-term relaxation respectively). The stability of $H_{EX}$ is fundamental for practical application of exchange bias systems. In this paper we report measurements of training and relaxation in FeNi films coupled with the antiferromagnet FeMn. We show that $H_{EX}$ suppressed both by training and relaxation was partially recovered as soon as a field cycling for consecutive hysteresis loop measurement was stopped or the magnetization of the ferromagnet was switched back to the biased direction.

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