• 한국자기학회지
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• 제8권6호
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• pp.374-379
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• 1998

Mn1-xCrxPt3 합금 박막을 유리기판상에 rf 마그네트론 스퍼터법으로 전이금속(Mn, Cr)과 Pt층을 적층하여 증착한우 열처리함으로써 제조하였다. 제조한 박막들의 소각 및 광각 x-선 회절 분석, 자기 히스테리시스 루우프, 커 스펙트럼을 실온에서 조사했다. 제조한 박막들은 (111)면이 막면에 평행으로 강하게 우선 배향된 AuCu3 형의 규칙합금 구조를 나타냈다. 포화자화는 Cr 치환량(x)이 증가함에 따라 감소하다가 x=0.58 부근에서 영에 가까워진 후 다시 증가하여 x=0.77 이상에서는 거의 일정한 값을 나타냇다. 이것은 페로자성인 MnPt3(x=0)에 Cr을 치환하며, Cr의 자기모멘트가 Mn과 반강자성적으로 결합하여포화자화가 감소하다가 Cr 치환량이 더욱 증가하면 Cr의 기여가 지배적이 되어 다시 증가하기 때문으로 생각된다. MnPt3의 경우에는 자화용이축이 막면에 평행이었으며, Cr 치환량이 증가합에 따라 수직자기이방성이 증가하여 x=0.58 이상에서는 수직자화막이 얻어졌다. 또한, 이 영역에서 Cr 치환량이 증가함에 따라 보자력도 증가하여 x=0.58 이상에서는 수직자화막이 얻어졌다. 또한, 이 영역에서 Cr 치환량이 증가함에 따라 보자력도 증가하여 CrPt3의 경우에는 약 4 kOe의 큰 값을 나타냈다. Cr 치환량에 따른 커 회전각의 변화 추이는 포화지화의 변화 추이와 경향이 유사했다. x=0.77과 x=1의 경우에는 근적외선 영역에서의 커 회전각이 기존의 광자기기록매체인 TbFeCo를 능가했다.

• 한국결정성장학회지
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• 제8권4호
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• pp.599-604
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• 1998

본 논문은 PZT 박막의 기억소자 응용을 위한 Pt 그리고 RuO2 박막을 조사하였다. 초고주파 마그네트론 스퍼터링 방법을 이용하여 하부전극을 성장하였으며, 조사된 실험변수는 기판온도, 가스 부분압, RF 전력 그리고 후열처리 등이다. 기판온도는 Pt, $RuO_2$박막의 결정구조 뿐만 아니라 표면구조 및 비저항 성분에 크게 영향을 주었다. Pt 박막의 XRD 분석으로 기판온도가 상온에서 $200^{\circ}C$까지는 (111) 그리고 (200) 면이 혼재하는 결과를 보였으나 $300^{\circ}C$에서는 (111) 면으로 우선 방위 성장 특성을 보였다. XRD와 AFM 해석으로부터 Pt 박막 성장시 기판온도 $300^{\circ}C$, RF 전력 80W가 추천된다. 산소 분압비를 0~50%까지 가변하여 조사한 결과 산소가 5% 미만으로 공급되면 Ru 금속이 성장되고, 산소 분압비가 10 ~40%까지는 Ru와 $RuO_2$ 상이 공존하였으며 산소 분압비가 50%에서는 순수한 $RuO_2$상만이 검축되었다. 이 결과로부터 RuO2/Ru 이층 구조의 하부전극 형성이 산소 가스 부분압을 조절하여 한번의 공정으로 성장 가능하며, 이런 구조를 이용하면 금속의 낮은 비저항을 유지하면서도 PZT 박막의 산소 결핍에 의한 기억소자의 피로도 문제를 완화할 것으로 사료된다. 후 열처리 온도를 상온에서부터 $700^{\circ}C$까지 증가할 때 Pt와 $RuO_2$의 비저항 성분은 선형적 감소 추세를 보였다. 본 논문은 강유전체 기억소자 응용을 위한 최적화된 하부전극 제적조건을 제시한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1590-1592
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• 1999

We have fabricated good quality superconducting $YBa_2Cu_3O_{7-{\delta}}$ thin films on Hastelloy(Ni-Cr-Mo alloys) with $CeO_2$ buffer layers by in-situ pulsed laser deposition in a multi-target processing chamber. Using one of electrical properties of YBCO superconducting which the resistance approaches to zero dramatically on transition temperature, we have researched to make power transmission line, we have deposited YBCO thin film on flexible metallic substrate. However, it is difficult to make films on flexible metallic substrates due to both interdiffusion problem between metallic substrate and superconducting layer and non-crystallization of YBCO on amorphous substrate. From early research, two ways-using textured metallic substrate and buffer layer-were proposed to overcome theses difficulties. We have chosen $CeO_2$ as a buffer layer which has cubic structure of $5.41{\AA}$ lattice parameter and only 0.2% of lattice mismatch with $3.82{\AA}$ of a-axis lattice parameter of YBCO on (110) direction of $CeO_2$. In order to enhance the crystallization of YBCO films on metallic substrates we deposited $CeO_2$ buffer layers at varying temperature $700^{\circ}C$ to $800^{\circ}C$ and $O_2$ pressure. By X-ray diffraction, we found that each domination of (200) and (111) orientations were strongly relied upon the deposition temperature in $CeO_2$ layer and the change of the domination of orientation affects the crystallization of YBCO upper layer.

• 한국결정학회지
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• 제3권2호
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• pp.120-128
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• 1992

BaTiO3 단결정을 용액의 서냉속도를 달리하면서 TSSG법으로 육성하였으며, 성장된 단결정의 결정외형, 결정 결함, 분역구조 등을 관찰하였다. 0.5℃/hr이 하의 속도로 서 냉함으로써 비교적 등차원적인 큰 단 결정을 육성할 수 있었으며, 성장된 BaTiO3 단결정 은 |111|면이 가장 잘 발달된 외형을 나타내었다. 용 액 냉각속도가 너무 빠르거나 용액내의 수직 온도구 배가 너무 크면 용액이 불안정해지므로, 침상의 Ba6 TiL7040 결정상이 석출된다. 성장된 결정내에 평행 한 쐐기모양의 lamella 분역 집단이 이와 수직하게 진행하는 lamella 분역 집단과 불규칙한 경계를 이루 고 있으며, 이들은 x-ray topography에서 현저한 회 절 명암 차이를 나타낸다. 단결정을 127℃ 이상으로 가열하면 입 방정으로 상전이 된다. 상전이 전단이 이 동할 때 정방정 영역에서는 연속적 분역 재배열이 이루어 지고 입방정 영역에서는 규칙적인 음력변형이 나타나며, BaTiO의 PTF정벽면은 |110|에 대해 약 9°기울어진 면으로 이루어진다.

• 열처리공학회지
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• 제31권6호
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• pp.269-274
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• 2018

Grain-oriented electrical steel sheets are mainly used as core materials for transformers and motors. They should have excellent magnetic properties such as low core loss, high magnetic flux density and high permeability. In order to improve the magnetic properties of the electrical steel sheet, it is important to form Goss oriented grains with a very strong {110}<001> orientation. Recently, efforts have been made to develop Goss grains by controlling processes such as hot rolling, cold rolling, and primary and secondary recrystallization. In this study, the sheets containing 3.2 and 3.4wt.% Si were used, which were rolled with 1 and 10 passes with total thickness reduction of 89%. Heating was carried out for primary recrystallization with different heating rates of $25^{\circ}C/s$ and $24^{\circ}C/min$ until $720^{\circ}C$. The behavior of Goss-, {411}<148>-, and {111}<112>-oriented grains were analyzed using X-ray diffraction(XRD) and electron back-scatter diffraction(EBSD) analysis. The area fraction of Goss-oriented grains increased with the number of rolling passes during cold rolling; however, after the primary recrystallization, the area fraction of the Goss grains was higher and exact Goss grains were found in the specimens subjected to rapid heating after one rolling pass.

• 복식
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• 제57권5호
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• pp.99-111
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• 2007

The purpose of this study were to identity face satisfaction and make-up behavior according to their lifestyles of middle aged women. The subjects were 350 women of 40 - 59 years old. The results of this study were as follow: 1. Lifestyle factors of middle aged women were self confidence, leisure activities, interests in appearance, economical efficiency, conservatism, and value-orientation. They were classified into four types of dignified & appearance interested group, passive stagnated group, unconfident & economic group, and value-oriented & leisure group according to their lifestyles. 2. They were satisfied with their eyes, lips, and eyebrows, but not satisfied with face tone, face shape, and skin texture. Total face satisfaction level was over average. The face satisfaction level of dignified & appearance interested group and value-oriented & leisure group were higher than other groups, but that of passive stagnated group was the lowest. 3. They pursued internal beauty and natural makeup, and did not follow trendy colors. Dignified & appearance interested group pursued characteristic, elegant, changeable, and various make-up colors, but value-oriented & leisure group pursued more various, changeable, and trendy colors. They did not prefer trendy products because of high price. Dignified & appearance interested group and unconfident & economic group were highly price-oriented, but value-oriented & leisure group purchased trendy products. 4. Dignified & appearance interested group included working women with not much income, but passive stagnated group included low-educated and non-working women. Unconfident & economic group included low-educated non-working women with not much income, but value-oriented & leisure group included highly-educated working women with high income.

• 한국세라믹학회지
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• 제35권3호
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• pp.280-286
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• 1998

LaAlO3 Single crystals used as a substrate for thin film depositions of a high temperature oxide su-perconductor YB2Cu3O7 and applied to microwave frequencies were grown by the Traveling Solvent Flati-ing Zone (TSFZ) method and characterized. For the growth of LaAlO3 single crystals polycrystalline fe-edrods were prepared from powder mixture of La2O3 and Al2O3 with a mole ratio of 1:1 calcined at 110$0^{\circ}C$ for 3h and sintered at 140$0^{\circ}C$ for 4h The growth LaAlO3 crystals was 4-5mm in diameter 30mm in length and dark brown. The growth rate was 2-3mm/h and the rotation speeds were 10rpm for an upper ro-tation and 40 rpm for a lower rotation The growing crystals and the feedrods were counter-rotated. The orientation of the grown single crystals of LaAlO3 was identified to be [111] direction. Dielectric constants were measured to be 30-33 between 100 kHz and 1 MHz in the 30$0^{\circ}C$ to 45$0^{\circ}C$ temperature range and 102 in a range of 100 kHz at the phase transformation temperature of 522$^{\circ}C$ Dielectric losses were calculated to be 1.8$\times$10-4 at the room temperature and 5.7$\times$10-3 at the phase transformation temperature. Lattice con-stants of the grown crystlals were determined to be aR=5.3806 $\AA$ and $\alpha$=60.043$^{\circ}$ by the least square method.

• 한국주조공학회지
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• 제29권2호
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• pp.64-69
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• 2009

In the present study the effect of cooling rate during solidification on the microstructural characteristics of Al-xAg (x = 31, 33, 35 at.%) in-situ binary eutectic composites has been investigated. To provide a wide range of cooling rate three different casting techniques, i.e. conventional casting, injection casting, and melt spinning have been used. The observed microstructure is very much dependent on the cooling rate. The fcc ${\alpha}$-Al and hcp $Ag_2Al$ phases exhibits an orientation of (111)Al//(0001)$Ag_2Al$, [1-10]Al//[11- 20]$Ag_2Al$. The microstructure of the melt-spun samples contains Widmanstatten structure resulting from solid-state transformation and nano scale two-phase structure resulting from solid-state phase separation. The microstructure of injection-cast samples contains eutectic structure and solid state phase-separated structure. On the other hand, conventional-cast samples exhibit a microstructure consisted of plate-type eutectic structure.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.111-120
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• 2000

Recently, metal oxide films such as MgO or ZrO$_2$ have been studied as buffer layers to fabricate the superconductor with preferred orientation and as diffusion barriers to prevent the reaction between superconductor and metal substrate. In this research, we focused fabrication and characterization of MgO and ZrO$_2$ films on textured metal substrates. We fabricated MgO and ZrO$_2$ films on the Ni metal sheets by sol-gel dipping method. The microstrcures of the films were investigated by SEM and AES analyses. The films were coated with different cycles and dryed at 400$^{\circ}$C and 500$^{\circ}$C . The final films were heat-treated at 700$^{\circ}$C, 800$^{\circ}$C, and 1000$^{\circ}$C, in air atmosphere. We investigated the alignment of MgO and ZrO$_2$ films on Ni metal sheets by XRD and pole figure. The grain growth of metal oxide films was improved by the increase of the drying temperature and annealing temperature. The grain growth was increased with the annealing temperature. The alignment of metal oxide films depended on the thickness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1418-1420
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• 1996

In this paper, structural properties of CdTe thin films and photovoltaic properties of thin film CdS/CdTe solar ceIl prepared by thermal vacuum evaporation were studied. Structural variation with $CdCl_2/heat$ treatment are assessed using x-ray diffraction and scanning electron microscopy. The crystal structure of CdTe films was zincblend type with preferential orientation of the (111) plane parallel to the substrate. The $CdCl_2$ treatment appears to increase the grain size of polycrystalline CdTe thin film. It was found that CdS/CdTe solar cell characteristics were improved by the heat treatment with $CdCl_2$. The conversion efficiency, however, decreased when heat treatment temperature was too high.