• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.210-219
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• 2000

The magnetoresistance characteristics of FeN/Co/Cu/Co and FeN/Co/Cu/Co/Cu/Co/FeN multilayers using ferromagnetic iron-nitrides (FeN) has been studied. The microstructure of FeN film is the mixed ${\alpha}$-Fe and $\varepsilon$-Fe$_3$N phase on the condition that the flow rate of N$_2$ gas is over 0.4 sccm. The magnetoresistance effect is observed because of shape magnetic anisotropy induced by needle-shaped $\varepsilon$-Fe$_3$N phase. This magnetoresistance effect changes, because the degree that the shape magnetic anisotropy adheres to the adjacent Co pinned layer is varied according to the flow rate of N$_2$ gas and the thickness of FeN film. The best magnetoresistance effect is obtained on the condition that the thickness of Co free layer is 70 ${\AA}$ and the maximum MR ratio(%) value of 3.2% shows in the FeN(250 ${\AA}$)/Co(70 ${\AA}$)/Cu(25 ${\AA}$)/Co(70 ${\AA}$)/Cu(25 ${\AA}$)/Co(70 ${\AA}$)/FeN(250 ${\AA}$) mutilayer film which is fabricated at the N, gas flow rate of 0.5 sccm and the FeN film thickness of 250 ${\AA}$. Four steps are observed in the magnetoresistance curve owing to this difference of coercive force, because respective magnetic layers in the multilayer possess different coercive forces. These effects observed in these mutilayer films can be expected to application to the memory device the same MRAM as can carry out simultaneously four signals.

• Journal of the Korean Magnetics Society
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• v.9 no.4
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• pp.210-216
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• 1999

The objective of this paper is to investigate corrosion behaviors of CoCrTa/CrNi thin film and post heat-treatment effect. An electron beam evaporator was used for films deposition. After evaporation, post heat-treatment was carried out under $5.0{\times}10^3$ Torr vacuum condition. Annealing temperature and time were 400 $^{\circ}C$ and 30 min, respectively. To understand the effect of annealing on corrosion behavior of CoCrTa/CrNi, potentiodynamic polarization technique and accelerated corrosion chamber test were undertaken. Corrosion potential is higher for the annealed samples (CoCrTa 400$\AA$/CrNi 1000$\AA$) than for as-deposited one. This is attributed to an enrichment of Cr in the surface layer of the thinfilm resulting in a more corrosion resistant material.

• Applied Microscopy
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• v.45 no.4
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• pp.225-229
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• 2015

Transition metal dichalcogenides (TMDs) are a class of two-dimensional (2D) materials that have attracted growing interest because of their promising applications. The properties of TMDs strongly depend on the crystalline structure and the number and stacking sequence of layers in their crystals and thin films. Though electrical, mechanical, and magnetic studies of 2D materials are being conducted, there is an evident lack of direct atom-by-atom visualization, limiting insight on these highly exciting material systems. Herein, we present our recent studies on the characterization of 2D layered materials by means of aberration corrected scanning transmission electron microscopy (STEM), in particular via high angle annular dark field (HAADF) imaging. We have identified the atomic arrangements and defects in 2H stacked TMDs, 1T stacked TMDs, distorted 1T stacked TMDs, and vertically integrated heterojunctions of 2D TMDs crystals.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.897-899
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• 1992

This paper deals with the characteristics of Indium Tin Oxide(ITO) sputtered by the reactive magnetron sputtering process. ITO films have been grown at various substrate temperatures(R.T, 100$^{\circ}C$, 200$^{\circ}C$, 240$^{\circ}C$) and we used the target material of alloy of Indium and Tin. The electrical and optical properties of the ITO film have been investigated and the effect of magnetic field to the properties of ITO was studied. We have studied how much the improvement of transmission rate and sheet resistivity by heat treatment was. The sample with good electrical and optical properties can be obtained for the low substrate temperature of 200$^{\circ}C$-250$^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 2001.02a
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• pp.214-214
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• 2001

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.812-816
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• 2017

$Fe_3O_4$ was prepared on the $TiO_2-coated$ natural mica substrate. The natural mica has an average particle size of $22{\mu}m$. The substrate was coated on $TiO_2$ thin films using hydrothermal synthesis at pH 1.5-2.5 at $75^{\circ}C$. The Fe precursor solution was prepared by mixing $FeSO_4$ (for $Fe^{2+}$ ion) and $FeCl_3$ (for $Fe^{3+}$ ions) with different molar ratios such as 1/2, 1/1, 2/1, 3/0, and $Fe_3O_4$ only. X-ray diffraction analysis shows that the crystal structure depends on the $FeCl_3-to-FeSO_4$ molar ratio. $Fe_3O_4$ crystal phase could be obtained at higher $FeSO_4$ contents.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1201-1207
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• 2010

In this study, a fatigue testing system capable of performing load-controlled tension-tension tests for micro-specimens was developed by using an electro-magnetic actuator. Using this system, fatigue testing as well as tensile testing can be performed over a wide range of loading frequencies. Further, a new laser interferometric strain/displacement gage was used during fatigue testing to obtain high-resolution measurements of the cyclic deformation of thin films. Since the testing machine and the displacement gage are stable and show quick responses, the displacement can be measured instantaneously and continuously during fatigue testing, and high-resolution results can be obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 1996.02a
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• pp.102-102
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• 1996

This paper represents a new type low power High Frequency technological ion source (HF TIS) for ion - beam processing: the surface modification of materials, cleaning of surface, sputtering, coating of thin films, and polishing. The operational principle of HF TIS is based on the excitation of electrostatic waves in plasma located in the external magnetic field. Low power HF TIS with diameter 92 rom gives the opportunity to obtain beams of inert and chemically reactive gases with currents range from 5 to 150 mA (current density $0.015\;~\;3.5\;mA/\textrm{m}^2$) and ion beam energy 100 ~ 2500 eV at a HF power level 10 ~ 150 W. Three grid concave type ion optical system (IOS) is used for extraction and formation ofion beam.n beam.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.350-350
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• 2011

The spin structure of Fe over layers on Cu (001), especially in region II is one of the unsolved problem for many years. We study the out - of - plane (OP) Fermi surfaces (FSs) of 7 monolayer Fe/Cu (001) films using angle resolved photo emission spectroscopy (ARPES). Ultrathin Fe was grown on Cu (001) substrate at room temperature and the experimental measurements were carried out at room temperature and low temperature. Fermi surfaces measured about $\frac{1}{4}$ of the Brillouin Zone (BZ) using photon energies ranging from 170 eV to 280 eV. Our results confirmed that ferromagnetic signal at 7 ML Fe on Cu (001) is nearly zero. These results are consistent with our recent x-ray magnetic circular dichroism (XMCD) and surface magneto - optic Kerr effect (SMOKE) experiments. Based on our observations we have made a simple model of this system, which explains all the experimental results.

• Textile Coloration and Finishing
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• v.23 no.2
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• pp.118-130
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• 2011

In this study, hydrophilic polyurethane (PU) was synthesized by one shot process to get good non-swelling effect and to keep high breathability using reactive silicone oil of mono terminal and bi-terminal types. We also blended non reactive silicone oil with pure hydrophilic PU to compare non-swelling effect and breathability with hydrophilic PU synthesized by the two types of reactive silicone oils. The hydrophilic films were analyzed by nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photo electron (XPS) spectroscopy, energy dispersive spectrometry (EDS), breathability, waterproofness, tensile strength, contact angle and swelling effect. The results showed that the film made by hydrophilic PU which was synthesized with mono terminal type silicone oil provided good non-swelling effect and acceptable moisture permeability due to the modified surface properties.