• Journal of the Korean Magnetics Society
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• v.7 no.4
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• pp.180-185
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• 1997

Variations of core loss and coercivity with heat treatment condition have been studied in amorphous ribbon core specimens. All measurements were performed at 10 kHz with a maximum induction of 0.1 T. With increasing annealing time, both core loss and coercivity of core specimens decreased first, reaching minimum values, and increased thereafter. Specimen heat treated in an air showed better soft magnetic properties than those treated in Ar atmosphere. The specimens annealed under magnetic field higher than 6 Oe in radial direction showed reduced core loss and coercivity. The field annealing effects were increased with increasing cooling rate near Curie temperature of the material. The specimen annealed under an applied field in perpendicular direction of the core showed increased coercivity and decreased permeability.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.173-178
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• 2001

The effects of heat-treatment with magnetic or non-magnetic field on magnetic properties of gas-atomized MPP dust cores subjected to various cooling processes after annealing were investigated. Upon magnetic-field annealing, ac permeability and core loss decreased with the increase of cooling rate, which were attributed to the generation of inhomogeneous internal stress and anomalous eddy current loss, respectively. It was not observed the formation of ordered phase and the related change in magnetic properties at the cooling stage for MPP dust cores. In MPP alloys, magnetic anisotropy was easily induced through the directional order, and permeability and core loss were changed under the conditions of low cooling rate and magnetic annealing.

• Journal of the Korean Magnetics Society
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• v.6 no.2
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• pp.80-85
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• 1996

An externally applied magnetic field during annealing the $Nd_{2}Fe_{14}B/Fe_{3}B$ based spring magnet was found to enhance the exchange coupling between the hard and soft magnetic grains. More than 30 % increase in remanence values for melt-spun $Nd_{4}Fe_{73.5}Co_{3}(Hf_{1-x}-Ga_{x})B_{18.5}$(x=0, 0.5, 1.0) alloys was resulted from uniform distribution of $Fe_{3}B$, $\alpha$-Fe as well as $(Nd_{2}Fe_{14}B)$, and also from reduced grain size of those phases by 20 %. The result also showed that there is an optimum grain size exhibiting a high coercivity value which will be discussed in terms of previously simulated exchange coupling parameter.

• Journal of the Korean Magnetics Society
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• v.5 no.4
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• pp.251-260
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• 1995

It has been reported that Co-based amorphous ferromagnetic alloys annealed in a small magnetic field develop a reproducible, asymmetric hysteresis loop. If the direction of the field during annealing is regarded as +, the magnetization reversal from - to + is smooth and reversible, with its slope determined by the demagnetizing field of the sample. This phenomenon is called the asymmetric magnetization reversal (AMR). The shape of the hyster-esis loop depends sensitively on the condition during the anneal and the alloy composition. Here, we report on the effect of the annealing temperature and time on AMR in a zero magnetostrictive ferromagnetic amorphous alloy. The AMR effect develops in a very short time at a reasonably high temperature, but is stabilized by annealing for a prolonged time.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.05a
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• pp.171-172
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2007.12a
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• pp.52-53
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 1991.11a
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• pp.93-99
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• 1991

• Proceedings of the Korean Magnestics Society Conference
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• 1999.10a
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• pp.48-49
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• 1999

• Journal of the Korean Magnetics Society
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• v.6 no.4
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• pp.242-250
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• 1996

The effects of annealing in magnetic field after deposition on electromagnetic properties of $Ni_{81}Fe_{19}$ thin($400\;{\AA}$) films prepared by RF-magnetron sputtering were investigated in terms of microstructure and surface morphology. The coercivity of the films was decreased below $300^{\circ}C$ due to stress relief and recrystallization, while increased at $400^{\circ}C$ due to grain growth and increasing the surface roughness. And then, $4{\pi}M_{s}$, was almost independent of annealing temperatures. Increasing the annealing temperature. the electrical resistivity of films was decreased from $37\;{\mu}{\Omega}cm$ to $24\;{\mu}{\Omega}cm$, the magnetoresistance was nearly a constant of about $0.6\;{\mu}{\Omega}cm$, and the MR ratio was increased from 1.5 % to 3.1 %. Therefore, It was shown that increasing the magnetoresistive ratio was mainly affected by decreasing the electrical resistivity. Considering the practical application of the films for magnetoresistive heads, optimal annealing conditions was obtained after one hour annealing at $300^{\circ}C$ in 400 Oe unidirectional magnetic field.

• Proceedings of the Korean Magnestics Society Conference
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• 1997.05a
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• pp.102-103
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• 1997