• Title/Summary/Keyword: B-H loop tracer

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Major B-H Loop Measurement of Toroidal Shape Magnetic Powder Core (토로이드형 분말코어의 Major B-H Loop 측정)

  • Son, Derac
    • Journal of the Korean Magnetics Society
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    • v.24 no.3
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    • pp.76-80
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    • 2014
  • Toroidal cores made of metallic powder requires large magnetic field strength up to few decade kA/m to obtain major hysteresis loop. To overcome thermal heat generation problem from large exciting current during measurement, we have employed a real time hysteresis loop tracer which can digitize and calculate B-H signals in personal computer as real time. For example, when we magnetize specimen at 10 Hz frequency, we could display hysteresis loops 10 times per second. Using the real time hysteresis loop tracer, we could measure major hysteresis loop of toroidal shape metallic powder core at maximum flux density or maximum magnetic field strength to be measured within 5 second not to significant increasement of specimen temperature due to the heat dissipation from coil windings. For the constructed hysteresis loop tracer, we could measure hysteresis loop at magnetic field strength higher than 50 kA/m for the toroidal shape specimen.

Measurement of AC Hysteresis Loops under Variable Tensile Stress for Amorphous Wire (비정질 세선의 인장응력에 따른 교류자기이력 특성측정)

  • 조희정;양종만;손대락;김구영
    • Journal of the Korean Magnetics Society
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    • v.3 no.1
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    • pp.61-64
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    • 1993
  • We have constructed a hysteresis loop tracer in order to measure the magnetic properties of amorphous wires under variable tensile stress. It has a force range of 0 N to 20 N and a magnetizing frequency of 1 kHz to 20 kHz. Using the ac-hysteresis loop tracer, we can measure the magnetic properties(maximum magnetic induction $B_{max}$, residual magnetic induction $B_{r}$, coercive field strength $H_{c}$, etc.) of amorphous wires with precision of 1% under variable tensile stresses.

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Construction of high frequency B-H Analyzer. (고주파 교류 자기특성의 컴퓨터 계측시스템 제작)

  • Kim, Ki-Uk;Song, Jae-Sung
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.1170-1172
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    • 1996
  • Analog-digital converter boards for use in personal computers have recently being improved markedly, many kinds of high speed(1 MHz - 10 MHz sampling rale) and over 12-bit vertical resolution A/D boards released. It can be applicable to high frequency magnetic measurements. In measurement of magnetic properties of high frequency, digitizing oscilloscope or trasient recorder are being used. but, those price are often expensive, we constructed PC controlled A-C B-H loop tracer that can measure Bs, Br, He, permeability and may be applied about 100 Hz - 20 kHz range. it use IBM PC compatible 1 M Sample/s, 12 bit A/D converter board with SSH(Simultaneous Sample and Hold).

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Magnetic Characterization of the Nd Based Permanent Magnet by Newly-Developed Bipolar Pulse-Type Hysteresis Loop Tracer

  • Rhee, J.R.
    • Journal of Magnetics
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    • v.4 no.3
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    • pp.73-75
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    • 1999
  • By appliying an slternate pulsed magnetic field -generated by using a sequential ignition circuit and a magnet exciting circuit- with peak value of about 10 T to the rod type Nd based magnet Nd2Fe12.7Cr1.3B with length of 5 mm and diameter of 3.6 mm, the basic magnetic properties such as saturation magnetization, residual magnetization, coercivity, maximum energy products, magnetic anisotropy and anisotropic field are investigated with obtaining the major and minor J-H loops of the magnet. The increase in coercivity due to eddy currents in ac measurement of coercivity is calculated considering eddy current loss by analyzing a wave of generating magnetic field. The average coercivity calculated for the magnet is about 12.2 kOe, anisotropy magnetic field and anisotropic constant are measured as 60 kOe 2.43 Mj/$m^3$, respectively.

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Development of Irreversible Micro-size Ferromagnetic Structures by Hydrogenation and Electron-beam Lithography (수소화 및 전자빔 사진식각 기술에 의한 비가역적 마이크로 크기의 강자성 구조체 개발)

  • Yun Eui-Jung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.1 s.343
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    • pp.7-12
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    • 2006
  • In this study, we developed irreversible and stable micro-size ferromagnetic structures utilizing hydrogenation and electron-beam lithography processes. The compositionally modulated (CM) Fe-Zr thin films that had average compositions $Fe_XZr_{100-x}$ with $x=65-85\%$ modulation periods of similar to 1 nm, and total thicknesses of similar to 100 m were prepared. The magnetic properties of CM Fe-Zr thin films were measured using a SQUID magnetometer, VSM and B-H loop tracer. After hydrogenation, the CM films exhibited larger magnetic moment increases than similar homogeneous alloy films for all compositions and かey showed largest increase in $Fe_{80}Zr_{20}$ composition. After aging in air at $300^{\circ}K$ the hydrogenated $Fe_{80}Zr_{20}$ CM films showed much larger magnetic moment increases, indicating that they relax to a stable, irreversible, soft magnetic state. The selective hydrogenation through electron-beam lithographed windows were performed after the circle shaped windows were prepared on $Fe_{80}Zr_{20}$ CM films by electron beam lithography. The hydrogenation through electron-beam resist and W lithographic techniques give a $49\%$ magnetic moment increase. This method can be applied to nano scale structures.