• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.267-267
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.264-264
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• 2003

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.10a
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• pp.91-91
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.137-137
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• 2005

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.167.2-167.2
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.49.2-49.2
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• 2008

• Journal of the Korean Magnetics Society
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• v.4 no.1
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• pp.7-11
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• 1994

Ferromagnetic resonance experiment was performed to study the variations of micromagnetic structure with heat treatment of melt spun $Fe_{76}Cu_{1}Nb_{3}Si_{14}B_{6}$ alloy for 1h at every $50^{\circ}C$ in the temperature range of $400^{\circ}C-700^{\circ}C$. The variations of micromagnetic structure was discussed qualitatively in terms of the variations of line width ${\Delta}H_{p-p}$ and resonance magnetic field $H_{res}$. With increasing armealing temperature to $400^{\circ}C$, ${\Delta}H_{p-p}$ decreases and $H_{res}$ increases due to the decrease in magnetic anisotropy resulting from structural relaxation during heat treatment. With increasing annealing temperature from 400 to $500^{\circ}C$, ${\Delta}H_{p-p}$ increases and $H_{res}$ decreases due to the increase in magnetic anisotropy resulting from the formation of nanocrystalline particles embedded in an amorphous matrix. With increasing armealing temperature from 500 to $550^{\circ}C$, ${\Delta}H_{p-p}$ decreases and $H_{res}$ increases due to the decrease in magnetic anisotropy resulting from the formation of homogeneous nanocrystalline structure with a minor amorphous phase. Further increase in armealing temperature above $550^{\circ}C$ C causes ${\Delta}H_{p-p}$ to increase and $H_{res}$ to decrease due to the increase in magnetic anisotropy due to the formation of inhomogeneous grain structure and intermetallic compounds.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.864-873
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• 1995

Amorphous $Fe_{73.5}Cu_{1}Nb_{3}Si_{16.5}B_{6}$ ribbons were annealed for different time at $500^{\circ}C$ and $552^{\circ}C$, just before and after the exothermic reaction in DSC curve. The development of nanocrystalline phase was investigated by means of $M\"{o}ssbsuer$ spectroscopy. The crystalline phase consists mainly of $DO_{3}Fe-Si$. Though slight in amount (5%), another ferromagnetic phase which could be presumed $t-Fe_{3}B$ was detected Si content of $DO_{3}Fe-Si$, Si/(Fe+Si), was 0.218 under the heat treatment at $500^{\circ}C$ for 60 min and 0.222 at $552^{\circ}C$ for 10 min. Since then both of those values decreased with time until 120 min and finally these two values remained constant at 0.210. The variation in Si content with annealing time results in the variation in the hyperfine field and the isomer shift. The increase in the mean hyperfine fields and the decrease in the mean isomer shifts of Fe-Si are caused by the increase in Si content. The volume fractions of residual amorphous phase rapidly decrease during the early stage of annealing and come nearer to saturation after 120 min both at $500^{\circ}C$ and $552^{\circ}C$. The decrease in the mean hyperfine field of residual amorphous. in spite of slight changes in the volume fractions of Fe-Si and of residual amorphous after 120 min. is caused by the increase in the content of Nb and B in residual amorphous phase. The saturated volume fraction of the crystalline phase was 81% for $500^{\circ}C$ (180 min) and 77% for $552^{\circ}C$ (960 min), different from expectation.

• Applied Microscopy
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• v.47 no.1
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• pp.50-54
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• 2017

The microstructure, the crystallization behavior, and magnetic properties of FeSi-based soft magnetic alloys (FINEMET) were investigated using transmission electron microscopy, X-ray diffraction, and coercive force measurements. The amorphous $Fe_{73.28}Si_{13.43}B_{8.72}Cu_{0.94}Nb_{3.63}$ alloys particles, prepared in $10^{-4}$ torr by gas atomization process, were heat treated at $530^{\circ}C$, $600^{\circ}C$, and $670^{\circ}C$ for 1 hour in a vacuum of $10^{-2}$ torr. Nanocrystalline Fe precipitation was first formed followed by the grain growth. Phase formation and crystallite sizes was compared linked to its magnetic behavior, which showed that excellent soft magnetic property can directly be correlated with its microstructure.

• Journal of the Korean Magnetics Society
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• v.8 no.1
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• pp.13-20
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• 1998

The crystallographic and high frequency characteristics of $Fe_{73.9}Cu_{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$ soft magnetic alloys were investigated under the magnetic field annealing. As-cast ribbon with which already imbedded nanocrystalline Fe-Si phase on the surface have a preferred orientation with (400) plane to surface and also with the [011] direction parallel to the ribbon length. The extra nanocrystalline Fe-Si phase appeared throughout at 45$0^{\circ}C$ in samples with or without the longitudinal magnetic field. However the formation of nanocrystalline phase does not appear on the suface layer until 50$0^{\circ}C$ annealing temperature under the transverse field. The cryststallization fraction of annealed samples with longitudinal magnetic field is higher than that of samples without magnetic field. When the transverse magnetic field is applied, the crystallization fraction does not increases but decreases until 50$0^{\circ}C$. However the crystallization of internal regions can be confirmed by X-ray diffraction measurement via tilting the sample. It was found that for all samples, the saturation induction were all same with 1.3 T. The coercive field of as-cast sample was 1.06 A/cm, but in annealed samples it decrease from 0.56 to 0.1 A/cm with increasing annealing temperature from 400 and 55$0^{\circ}C$, respectively. The squareness of annealed samples under transverse magnetic field has a small value than that of both without field and with longitudinal field annealing.