• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.1032-1038
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• 2000

Ni$_{81}$$Fe_{19}$(200 nm) thin films have been deposited by RF-magnetron sputtering on Si(001) substrates, Atomic force microscopy(AFM), X-ray diffraction(XRD) and magnetoresistance(MR) measurements of the thin films for investigating electromagnetic properties and microstructures were employed. During field annelaing for 1hr, there was no big difference n XRD patterns of Ni$_{81}$$Fe_{19}$ thin films. However, there was a significant change in XRD patterns of Ni$_{81}$$Fe_{19}$ thin films deposited at 40$0^{\circ}C$ during in-situ magnetic field deposition. The degree of surface roughness increased with increasing annealing and deposition temperature. With variation of surface roughness, there was no significant difference in MR Characteristics of Ni$_{18}$ $Fe_{19}$ thin films in 1hr-annealed case. High MR ratio was observed in the case of in-situ field deposited Ni$_{81}$$Fe_{19}$ films. 19/ films.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.113-118
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• 2008

We have developed an integrated giant magneto resistance using not only circuit but also integrating technique with semiconductor for automobile application. It has four elements used for giant magneto resistance sensor. Ni-Fe/Cu multi layers were prepared on a glass substrate by magnetron sputtering. The dependence of magneto resistance on the thickness of the Ni-Fe and Cu layers was investigated. The MR ratio showed a saturated a peak at Cu layer $10{\AA}$, Ni-Fe layer $50{\AA}$, where the MR ratio is about 8.7% at room temperature. By means of Ni-Fe multi film and specific integrating technique, these new giant magneto resistance sensor showed excellent resistance characteristics.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.279-282
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• 2006

Magnetic tunnel junctions (MTJs), which consisted of amorphous ferromagnetic NiFeSiB free layers, were investigated. The NiFeSiB layers were used to substitute for the traditionally used CoFe and/or NiFe layers with the emphasis being given to obtaining an understanding of the effect of the amorphous free layer on the switching characteristics of the MTJs. $Ni_{16}Fe_{62}Si_{8}B_{14}$ has a lower saturation magnetization ($M_{s}:\;800\;emu/cm^{3}$) than $Co_{90}Fe_{10}$ and a higher anisotropy constant ($K_{u}:\;2700\;erg/cm^{3}$) than $Ni_{80}Fe_{20}$. The $Si/SiO_{2}/Ta$ 45/Ru 9.5/IrMn 10/CoFe $7/AlO_{x}/CoFeSiB\;(t)/Ru\;60\;(in\;nanometers)$structure was found to be beneficial for the switching characteristics of the MTJ, leading to a reduction in the coercivity ($H_{c}$) and an increase in the sensitivity resulted from its lower saturation magnetization and higher uniaxial anisotropy. Furthermore, by inserting a very thin CoFe layer at the tunnel barrier/NiFeSiB interface, the TMR ratio and switching squareness were improved more with the increase of NiFeSiB layer thickness up to 11 nm.

• Journal of the Korean Magnetics Society
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• v.9 no.6
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• pp.291-295
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• 1999

$NiFe/Co/Al_2O_3/Co/IrMn$ tunneling junctions were grown on (100)Si wafer and their spin-valve tunneling magnetoresistance (TMR) was studied. The tunneling junctions were grown by using a 5-gun RF/DC magnetron sputter. $Al_2O_3$ barrier layer was formed by exposing Al layer to oxygen atmosphere at 6$0^{\circ}C$ for 72 hours. Strong exchange coupling interaction is observed between the ferromagnetic Co and the antiferromagnetic IrMn of Co/IrMn bilayer when IrMn is 100$\AA$ thick. $NiFe(183\;{\AA})/Co(17\;{\AA})/Al_2O_3(16\;{\AA})/Co(100\;{\AA})/IrMn(100\;{\AA})$ tunneling junction shows best TMR ratio of about 10% in the applied magnetic field range of $\pm$20 Oe. The TMR ratio is improved about 23% and electrical resistance is decreased about 34% when annealed at 200 $^{\circ}C$ for 1 hour in magnetic field of 330 Oe, parallel to the bottom electrode. With increasing the active area of junction the TMR ratio increases while electrical resistance decreases.

• YAKHAK HOEJI
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• v.17 no.4
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• pp.235-243
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• 1973

Determinations of the compositioin ofl chinoform metal chelates by elemental analysis and molar ratio method showed that the ratios of the ligand to metals in chinoform Cu(II) chelate, chinofrm Ni (II) chelate, and chinoform CO(II) chelate were 2:1 respectively and that the ratio in chinoform Fe(III) chelate was 3:1. It was found that diffe rential thermal values vary with the center metalic ions and that the thermal stability was in anorder of Fe>Cu>Co>Ni. The indices of over-all stability constant of chinoform Cu(II) chelate, Ni(II) chelate, Co(II) chelate, and Fe(III) chelate were 15.57, 15.16, 15.40 and 20.76, respectively, and the over-all stability was in an order of Fe>Cu>Co>Ni. The tests of the natibacterial activity in vitro of the chinoform metal chelates against Staphylococcus aureus ATCC G538, Pseudomonas aeruginosa 2131, Serratia marcescens 3357, Klebsiella pneumoniae 8899, Enterococcus 3309, Streptococcus pyogenes 507, and Escherichia coli 125 showed that the Cu(II) chelate generally had greater activity than chinoform, that it had four-fold activity particularly against Streptococcus pyogenes 507 and Staphylococcus awreus ATCC 6538, that the Ni(II) and Co(II) chelates had almost same activity, and that the Fe chelate had strong activity against Escherichia coli 125.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.888-892
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• 2004

It is necessary to develop soft magnetic layer with high saturation magnetization 4 $\pi{M}_s$ and in-plane magnetic anisotropy field Hk for soft magnetic underlayer of perpendicular magnetic recording media with high signal to noise ratio. Fe-Co-B layer with high 4 $\pi$Ms of about 23 kG deposited on Ni-Fe and Ni-Fe/Si seedlayer exhibited very high in-plane magnetic anisotropy filed Hk of about 280 and 380 Oe, respectively, In-plane XRD studies clarified that the lattice spacing of planes along the easy axis direction was longer than that along the hard axis direction in the Fe-Co-B layers with high Hk. These results indicate that high Hk of Fe-Co-B/Ni-Fe and Fe-Co-B/［Ni-Fe/si］ layers were resulted from magnetoelastic anisotropy owing to a residual stress. Moreover, the high Hk in the Fe-Co-B/Ni-Fe layer was maintained until 30$0^{\circ}C$ annealing temperature.

• Journal of the Korean Magnetics Society
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• v.5 no.3
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• pp.191-196
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• 1995

NiCuZn ferrites were prepared by a solid-state reaction and sintered at $900^{\circ}C$ for 5 hours. Its properties were investigated by controlling the ferrite composition and processing. NiCuZn ferrite with a composition of ${(Ni_{0.2}Cu_{0.2}Zn_{0.6}O)}_{1.02}{(Fe_{2}O_{3})}_{0.98}$ was found to have the maximum initial permeability as a result of the variation of Cu content and the (Ni+Cu)/Zn ratio. Curie temperature($T_{c}$) of NiCuZn ferrite was decreased with the larger Cu content and increased with the larger Ni content. NiCuZn ferrites of ${(Ni_{0.2}Cu_{0.2}Zn_{0.6}O)}_{1-w}{(Fe_{2}O_{3})}_{1+w}$ composition milled for 20~80 hours had the maximum initial permeability at w=-0.015 and Curie temperature ($T_{c}$) was decreased with the increasing of $Fe_{2}O_{3}$ deficiency(w).

• Journal of Magnetics
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• v.9 no.3
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• pp.79-82
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• 2004

The structure and magnetic properties of Fe-Ni-N/Cu multilayered films, prepared by the DC magnetron sputter, as a function of different thicknesses of Fe-Ni-N ($t_{FeNiN}$) and Cu ($t_Cu$) layers have been studied by the methods of x-ray diffraction and measurement of magnetic moment. It has been found that the enhancement of (200) orientation in Fe-Ni-N layers is observed at the ratio of layer thickness with about $t_{FeNiN}/t_{Cu}$ $\underline{\simeq}$ 3.75. The reduction of magnetization due to the formation of interdiffusion near the interface is explained by means of the dead layer model. The temperature dependence of magnetization exhibits the feature of Blochs $T^{\frac{2}{3}}$ law. The layer thickness dependence of Curie temperature has been discussed by critical temperature theory of Heisenberg model.

• Korean Journal of Metals and Materials
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• v.50 no.6
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• pp.419-425
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• 2012

The purpose of this research was to develop a low Ni austenitic cast iron through replacing Ni by Cu and Mn because they are cheaper than Ni. The effect of the Cu content (6-12 wt%) on the microstructure characteristics was investigated in Fe-3%C-16%(Ni+Cu+Mn) cast iron. Contrary to general effect of the Cu on cast iron, the result of the microstructure analysis indicated that bainite and cementite were formed in high Cu content (>8 wt%Cu). A crystallized Cu-solution (Cu-Mn) phase and MnS in the Cu-solution were formed. The quantity of those phases increased as the Cu content increased. Consequently, the high Cu content in the composition ratio (Ni+Cu+Mn=16%) caused the formation of Cu-Mn/MnS and those phases decreased the effect of Cu and Mn on austenite formation. For this reason, bainite and cementite were formed in high Cu content.

• Journal of the Korean Magnetics Society
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• v.5 no.3
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• pp.203-209
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• 1995

A study of the dependence of the magnetoresistance in $glass\[Cu_{x\AA}\NiFe_{50\AA}\Cu_{x\AA}\Co_{50\AA}](X;\=\;8,\;10,\;14,\;18,\;22,\;26,\;28,\;38,\;48,\;58\;\AA,\;N\;=\;2,\;3,\;4,\;10,\;20)$ multilayers prepared by dc magnetron sputtering on the interlayer thickness of Cu (X), the number of multylayer(N) and annealing temperature has been performed. Resistance measurement were made by four terminal method, and the magnetic field applied to perpendicular and parallel for the current. The maximum magnetoresistance(MR) ratio(%) was appeared in the vicinity of $10\;\AA$ in Cu layer, and it was oscillated with the thickness of Cu. The MR ratio was increased with the number of layers N, however the ratio for the N = 4 layers decreased rather than the N = 3 layers. The dependence of the ratio on the annealing temperature was increased to $250^{\circ}C$.