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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Magnetics Society
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Journal DOI :
The Korean Magnetics Society
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Volume & Issues
Volume 19, Issue 6 - Dec 2009
Volume 19, Issue 5 - Oct 2009
Volume 19, Issue 4 - Aug 2009
Volume 19, Issue 3 - Jun 2009
Volume 19, Issue 2 - Apr 2009
Volume 19, Issue 1 - Feb 2009
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Attempt Frequency of Magnetization in Synthetic Antiferromagnet
Sur, Hong-Ju ; Lee, Kyung-Jin ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 1~4
DOI : 10.4283/JKMS.2009.19.1.001
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.
EMGF Output Analysis Using Inductance Variation Model
Kim, Tae-Shin ; Sung, In-Mo ; Yang, Ji-Hyuk ; You, Chun-Yeol ; Kwon, Oh-Kyu ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 5~11
DOI : 10.4283/JKMS.2009.19.1.005
The Explosive Magnetic Generator of Frequency (EMGF) has been studied as a method to generate a strong microwave effectively through converting the explosion powder energy into the electromagnetic energy. However, the generated high frequency electromagnetic wave has not been explained clearly yet, for it is known to be difficult to analyze the high frequency electromagnetic wave oscillation using a simple time-varying equivalent circuit model. In this paper, we analyze the problems of the widely used inductance model with an exponential decreasing pattern and investigate the tendency of a more accurate inductance variation model using the finite element method of EMGF inductance by considering the magnetic compression effect. And we have shown via an EMGF output simulation that the new inductance variation model proposed here has an negative effect on EMGF output.
The Effect of Ba and Fe Concentration on Soft Magnetic Properties of Z-Type Barium Ferrite
Cho, Kwang-Muk ; Nam, In-Tak ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 12~16
DOI : 10.4283/JKMS.2009.19.1.012
Z-type barium ferrite [(
= 3, 5, 7, 13 wt%.
= 5, 7, 10 wt% )] were synthesized using co-precipitation method. The microstructure and magnetic properties of synthesized particles were investigated. In all prepared particles M-type Ba ferrite is identified with Z-type Ba ferrite together. It is found that particles having 7 wt% for Ba and 5 wt% for Fe excess addition revealed high saturation magnetization, respectively. All synthesized particles showed relatively high coercivity for device application. This result may be attributed to the contribution of M-type Ba ferrite. Ba and Fe excess addition was not affected to the structural change of CoZnZ Ba ferrite. The certain amount of excess additions of Ba and Fe and the 2 step heat-treatment may be beneficial to the improvement of soft magnetic properties of Z-type barium hexa-ferrite
Influences of Operation Frequency and Excitation Current on Output Signal of Orthogonal Fluxgate Sensor Fabricated with an Amorphous Wire
Shin, Kwang-Ho ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 17~21
DOI : 10.4283/JKMS.2009.19.1.017
In this study, we have investigated that the excitation current and operation frequency dependences of the output properties of the orthogonal fluxgate sensor which was fabricated with a Co base amorphous wire and a pick-up coil. The output signal increased linearly with increase of the excitation current below 0.3 A, and decreased with increase of the excitation current over 0.6 A. It was also found that the output increased sensitively with increase of operation frequency below 1.3MHz. The output was 3.8 V at the frequency of 1.3MHz while 1.32 V at 1MHz.
Technology Trend of Spin-Transfer-Torque Magnetoresistive Random Access Memory (STT-MRAM)
Kim, D.K. ; Cho, J.U. ; Noh, S.J. ; Kim, Y.K. ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 22~27
DOI : 10.4283/JKMS.2009.19.1.022
Reduction of the critical current density (
) for STT magnetization switching is most important issue of magnetic tunnel junctions (MTJs) based MRAM. This report describes how to decrease the Jc and will introduce the recent research progresses of STT-MRAM devices with material engineering and structural improvement, respectively.
Research Status and Prospectives of Magnetic Nanoparticles in Bio-medical Applications
Min, J.H. ; Song, A.Y. ; Kim, Y.K. ; Wu, J.H. ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 28~34
DOI : 10.4283/JKMS.2009.19.1.028
Magnetic nanoparticles are widely used for bio-medical applications such as MRI contrast agents, drug-delivery systems, cell separation and hyperthermia, thanks to their unique magnetic properties and physico-chemical characteristics. In the early stage, efforts were focused on synthesis of uniform nanoparticles of desired dimension to achieve targeted, stable functionalities. Recently, it has been of great interest in dispersion of such nanoparitcles in aqueous solution and to render the nanoparticles bio-compatible with biofunctionality on request for utilization in bio-medical fields. In this paper, we survey the research status and give prospective on future work of magnetic nanoparticles for biomedical applications.
Patent Analysis of MRAM Technology
Noh, S.J. ; Lee, J.S. ; Cho, J.U. ; Kim, D.K. ; Kim, Y.K. ; Yoo, Y.M. ; Ha, M.Y. ; Seo, J.W. ;
Journal of the Korean Magnetics Society, volume 19, issue 1, 2009, Pages 35~42
DOI : 10.4283/JKMS.2009.19.1.035
Among the next generation memory, MRAM (Magnetic Random Access Memory) is worthy of notice for substituting the preexisting memory thanks to its non-volatile property and other advantages. Recently perpendicular MRAM and spin transfer torque MRAM techniques are under active investigation to realize a high density and low power consumption. As a result, there are increasing of patents applications for high density, low current density for magnetization switching and high thermal stability. In this paper, we analyze the trend of patent applications and registrations about MRAM and propose a direction of future investigation.