• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.597-600
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• 1995

The effects of surface oxidation on magnetic properties were investigated at high frequencies (10k-100MHz) for $7-18\mu\textrm{m}$ thick $Co_{70}Fe_{5}Si_{15}B_{10}$ amorphous ribbons with controlled domain structure. Oxidation was accelerated by acid-treatment or anodic oxidation treatment, and the insulation layers were prepared on the surfaces of the ribbons. The acid-treatment was effective in improving permeability and magnetic loss. Although the anodic oxidation treatment was effective in both making oxide layer and thinning, the magnetic properties were not improved compared with the case of the acid-treatment.

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.7-7
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• 2005

• Transactions on Electrical and Electronic Materials
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• v.12 no.1
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• pp.20-23
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• 2011

Amorphous Ti-(50-x)Ni-xCu (at%) (x = 20, 25, 27, 30) alloy ribbons were prepared by melt spinning. Subsequently, the crystallization behavior of the alloy ribbons was investigated by X-ray diffraction and differential scanning calorimetry. ${\Delta}T$ (the temperature gap between $T_g$ and $T_x$) increased from 33 K to 47 K and the wavenumber ($Q_p$) decreased from 29.44 $nm^{-1}$ to 29.29 $nm^{-1}$ with increasing Cu content from 20 at% to 30 at%. The activation energy for crystallization decreased from 188.5 kJ/mol to 170.6 kJ/mol with increasing Cu content from 20 at% to 25 at%; afterwards, the activation energy remained near constant. Crystallization occurred in two-stage: amorphous-B2-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content less than 25 at%, while it occurred in three-stage; amorphous-B2-TiCu-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content more than 27 at%.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.379-384
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• 1992

The Fe-base amorphous ribbons with 15mm width and about 20x10S0-6Tm thickness, (FeS179-xTCrS1xT)BS116TSiS15T and (FeS181-xTMnS1xT) BS112TSiS17T (x:0-6), were prepared melt spinner. The thickness of the ribbons followed by PFC (Planar Flow Casting). The initial permeability and total core losses were measured as a function of additive elements (Cr, Mn) and annealing conditions in high frequency for the purpose of using these materials as a core of magnetic amplifier and switched mode power supplies. The initial permeabilities were enhanced and core losses were decreased by non-magnetic field annealing in proper conditions. The lowest core loss in 0.2T/10kHz was measured at 3% Cr addition amorphous ribbon, and the loss was 5.6W/kg. The permeability of the ribbon at 10kHz was about 9000.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.252-252
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.20-20
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• 1996

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.72-72
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• 1994

• Current Applied Physics
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• v.18 no.12
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• pp.1523-1527
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• 2018

The thermal stability, magnetic and magnetocaloric properties of $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) melts-pun ribbons were studied. The relatively high reduced glass transition temperature ($T_{x1}/T_m$ > 0.60) and low melting point ($T_m$) resulted in excellent glass forming ability (GFA). The Curie temperatures ($T_C$) of melt-spun amorphous ribbons $Gd_{55}Co_{35}M_{10}$ for M = Si, Zr and Nb were 166, 148 and 173 K, respectively. For a magnetic field change of 2 T, the values of maximum magnetic entropy change $(-{\Delta}S_M)^{max}$ for $Gd_{55}Co_{35}Si_{10}$, $Gd_{55}Co_{35}Zr_{10}$ and $Gd_{55}Co_{35}Nb_{10}$ were found to be 2.86, 4.28 and $4.05J\;kg^{-1}K^{-1}$, while the refrigeration capacity (RC) values were 154, 274 and $174J\;kg^{-1}$, respectively. The $RC_{FWHM}$ values of amorphous alloys $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) are comparable to or larger than that of $LaFe_{11.6}Si_{1.4}$ crystalline alloy. Large values of $(-{\Delta}S_M)^{max}$ and RC along with good thermal stability make $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) amorphous alloys be potential materials for magnetic cooling operating in a wide temperature range from 150 to 175 K, e.g., as part of a gas liquefaction process.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.88-89
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• 2003

During the past decade, giant magnetotransport phenomena such as giant magetoresistance (GMR) in thin films and in manganese perovskites, and, giant magnetoimpedance (GMI) in soft magnetic amorphous ribbons, have brought much interest in the basic physical understanding and their applications as magnetic recording heads and in magnetic sensors technology. Among the parameters required for the quality of a magnetic sensor, temperature dependences of GMR and GMI profiles are playing an important role. In the present work, we have studied temperature dependences of the longitudinal permeability and giant magnetoimpedance effect in $Co_{70}$F $e_{5}$S $i_{15}$ N $b_{2.2}$C $u_{0.8}$ $B_{7}$ amorphous ribbons expecting as a promising candidate in the domain of magnetic sensors.rs.rs.rs.s.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.208-209
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• 2002

Recently an asymmetric giant magnetoimpedance (GMI) profile has been observed in Co-based amorphous ribbons annealed at the weak field [1-4]. This phenomenon has attracted a large interest due to its practical application to sensitive magnetic sensors. It is known [5.6] that in magnetic materials, the magnetoimpedance is caused by the effect of the magnetic field on the transverse magnetic permeability of a near-surface layer. In consequence of it, the value of the magnetoimpedance depends strongly on near-surface magnetic properties of the sample. (omitted)