• Title/Summary/Keyword: Permalloy

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A Study on FDTD Analysis and Fabrication of the Sheet-type Millimeter EM wave Absorber

  • Kim, Dae-Hun;Soo, Dong-Soo;Kim, Dong-Il
    • Journal of Navigation and Port Research
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    • v.34 no.4
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    • pp.299-304
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    • 2010
  • In this paper, the EM wave absorber was developed for the 94-GHz detecting radar system. To analysis an EM wave absorber in millimeter wave band, we fabricated three absorber samples using carbon black and titanium dioxide and permalloy with chlorinated polyethylene. After measuring the complex relative permittivity, the absorption characteristics are simulated by 1D FDTD according to different thicknesses of less than 1.0 mm. Then, the EM wave absorber was fabricated based on the FDTD simulation. As a result, the measured results agreed well with the simulated ones, and the developed EM wave absorber with a thickness of 0.7 mm had the desired absorption characteristics of more than 14 dB in the frequency range of the 94-GHz band.

Fabrication and characteristics of soft magnets on paper (연자성 박막 제지의 형성 및 특성)

  • 김용성;신경호;김광호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.96-99
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    • 2001
  • The formation of soft magnets on paper(SMOP) is proposed for the first time and we have demonstrated it successfully. Iorn was used to form the soft magnet thin film on paper. And Cr layer was used as a buffer layer because the roughness of substrate(paper) is not negligible. The maximum magnetization of Cr/Fe/Cr/Paper(Fe:5000${\AA}$) is about 1000 [emu/cc] and the coercive field is about 80 [Oe.]. It is necessary to reduce the coercivity and to enlarge the magnetization value of SMOP to perform a good soft magnetic characteristics on paper. On, the permalloy material is the proper candidate for its high permeability, low coercivity and high magnetization values.

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Improved Linearity and Saturation of Current Sensor by Laminating Silicon Steel and Fermalloy (퍼멀로이와 실리콘스틸의 적층 통한 전류센서의 선형성 및 포화도 개선)

  • Shin, Jung-Won;Choi, Bong-Seok;Ha, Yeong-Ho
    • Journal of Sensor Science and Technology
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    • v.24 no.3
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    • pp.194-201
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    • 2015
  • The current sensor is used in industrial devices and power utilities. Core materials of these current sensors are divided into mainly two groups as silicon steel and fermalloy. Silicon steel has a wide saturation bandwidth but low sensitivity during low-current, whereas permalloy has a short saturation bandwidth but high sensitivity during low-current. In this paper, laminated silicon steel and permalloy by equal ratio is proposed to improve the linearity and saturation of current sensor. It is proved that the proposed core material has larger bandwidth than fermalloy as well as higher sensitivity than silicon steel. When comparing simulation results by FLUX 3D, the proposed method has also better performance than the previous core materials.

Effect of cross-sectional vortex formation on magnetization reversal in rectangular shaped Permalloy nanowires

  • Khan, Imran;Hong, Jisang;Hwang, Chanyong
    • Proceedings of the Korean Magnestics Society Conference
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    • 2013.12a
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    • pp.115-115
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    • 2013
  • In order to pinpoint the different factors responsible for magnetization reversal, we performed simulation using OOMMF micromagnetic package for rectangular shaped permalloy element having length of $1{\mu}m$, width 50-100 nm and thickness 15-80 nm with length to width ratio L/W>4. Interestingly an increase in coercivity with thickness is found for every width below a critical thickness. With increasing width and thickness, the distinct behavior of coercivity, hysteresis loops and reversal mechanism are presented. Vortex end domains are observed during the magnetization reversal beyond particular thickness, where the three dimension reversal mechanism is expected to begin, causing a sudden increase in coercivity.

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GMR and Magnetization Study of Sputtered Permalloy/Cu Multilayer: The Influence of Temperature, Thickness and Number of Magnetic Layer

  • Lucinski, T.;Stobiecki, F.;Urbaniak, M.
    • Journal of Magnetics
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    • v.4 no.1
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    • pp.17-21
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    • 1999
  • The GMR ($d_Cu$) oscillatory behaviour as well as the widths of first and the second antiferromagnetically coupled ranges of the Permalloy ($Py=Ni_{83}Fe_{17}$)/Cu multilayers have been found to be strongly affected not only by the presence of the superparamagnetic/paramagnetic entitles located at the Py/Cu interfaces but mainly by the existence of the magnetic bridges between Py layers. The effectiveness of the magnetic bridges has been found to be temperature dependent, leading to the temperature dependence of the remnant to saturation magnetization ratio ($M_R/M_S$). We have found that for Py/Cu multilayers with equal Py and Cu layer thicknesses a high field sensitivity of the GMR effect (0.4%/Oe) and negligible hysteresis can be achieved when the number of Py layers decreases from 100 to 6. Sensitivity can be further improved by increasing the Py layers thickness, but the hysterstic effect becomes more pronounced then.

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A Study on the Anisotropy Inhomogeneity of Permalloy Thin Films (퍼말로이 박막의 이방성불균일에 관한 연구)

  • 장평우;최태원;유성초;김희중
    • Journal of the Korean Magnetics Society
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    • v.7 no.4
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    • pp.186-190
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    • 1997
  • We measured an anisotropy inhomogeniety and dispersion of rf sputterd permalloy thin films by TBP(Transverse Biased Permeability) measurement method. Angular distribution function had a shape similar to the Lorentzian distribution, but magnitude distribution function deviates from the sysmetric Lorentzian distribution because of long tail to the region of a high Hk value. With increasing film thickness, the angular and magnitude anisotropy dispersion increased. The increase of angular dispersion was due to both the increase of grain size and local anisotropy in thicker films.

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Magnetic Properties of Permalloy(PB, PC) Strips Fabricated by Powder Rolling Process (분말 압연에 의해 제조된 퍼말로이(PB, PC)의 자성 특성)

  • 이동원
    • Journal of Powder Materials
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    • v.3 no.1
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    • pp.13-24
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    • 1996
  • Two grades of Permalloy strips, Fe-45Ni(PB) and Fe-78Ni-4Mo-5Cu(PC) were fabricated by powder rolling process from elemental powder mixtures. The roll compacted green strips were sintered, homogenized, cold rolled with or without an intermediate annealing and finally heat treated to measure magnetic properties. For a given thickness reduction, rolling with an intermediate annealing was found more effective to achieve a full densification with no visible micropores and also to obtain better magnetic properties. Increasing the final rolling reduction also produced a marked improvement of the magnetic properties whereas the cooling rate during the final heat treatment has little effect in both grades. Addition of a small amount, 0.4% Mn slightly degraded the properties. As an overall, The PM strips produced via powder rolling yielded the similar soft magnetic properties to the corresponding commercial grades produced via wrought processing.

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