• Progress in Superconductivity
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• 제8권1호
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• pp.75-80
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• 2006

[ $Yb_2O_3$ ] films were successfully deposited on a cube-textured Ni and(100) $SrTiO_3$(STO) single crystal substrates by metal organic chemical vapor deposition(MOCVD) method using $H_2O$ vapor as an oxidant. $H_2O$ vapor was used in order to avoid the oxidation of Ni substrate. The working pressure and Ar flow rate were 10 Ton and 600 sccm, respectively. $Yb_2O_3$ films on STO were formed at high temperatures above $900^{\circ}C$. While XRD peaks from $Yb_2O_3$ were hardly detected at $900^{\circ}C$, the $Yb_2O_3$(400) texture was developed fur the films grown at deposition temperatures above $950^{\circ}C$. The AEM surface roughness of $Yb_2O_3$ film, grown on STO, was in the range of $6{\sim}10nm$ for the film deposited at $950^{\circ}C$ with a $H_2O$ vapor partial pressure of 5.5 Ton and deposition times of 3 and 5 mins. For cube-textured Ni substrate, both $Yb_2O_3$(222) and $Yb_2O_3$ (400) textures were developed textures at deposition temperatures above $850^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.268-268
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• 2006

YBCO 초전도 박막을 제조하기 위해 일반적으로 사용되는 RABiTS공정을 통해 제조된 양축 정렬된 Ni 선재 위에 직접 YBCO를 증착시키려는 시도가 많이 이루어졌다. Ni 위에 직접 증착시킨 YBCO 박막은 c-축으로 정렬되는 온도에서 Ni이 확산되어 YBCO와 반응하여 초전도 물성을 약화시킨다. 이것을 방지하기 위하여 완층층을 먼저 증착을 하는 연구를 시행하였다. 본 연구는 Ni-5at.%W(100) 기판위에 hot-wall type MOCVD (metal organic chemical vapor deposition)를 이용하여 증착을 실시하였다. 완층층으로는 Ni, YBCO와 각각 4.70%, 3.32%의 lattice mismatch를 갖는 $Yb_2O_3$를 선택하였으며, 증착 조건으로는 온도 $800\;{\sim}\;1000^{\circ}C$, 시간 3 ~ 10min, 증착압력 10 Torr의 조건에서 증착을 행하였다. $Yb_2O_3$를 형성하기 위해 산소를 이용하였으나 $Yb_2O_3$(200) 형성을 방해하는 NiO(111)이 형성되었다. 산소를 대신해 수증기를 이용하여 NiO 상이 없는 $Yb_2O_3$(200)을 형성하였다. 증착 시간과 수증기 압력에 따른 $Yb_2O_3$의 $I_{(200)}/(I_{(111)}+I_{(200)})$의 상대 회절강도비를 XRD (X-ray diffraction)를 이용하였고, 증착된 표면 형상은 SEM(scanning electron microscopy)을 통해 관찰하였다.

• 한국표면공학회지
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• 제45권6호
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• pp.242-247
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• 2012

Yb-doped ITO (ITO:Yb) films were deposited on unheated non-alkali glass substrates by magnetron cosputtering using two cathodes (DC, RF) equipped with the ITO and $Yb_2O_3$ target, respectively. The composition of the ITO:Yb films was controlled by adjusting the RF powers from 0 W to 480 W in 120 W steps with the DC power fixed at 70 W. The ITO:Yb films had a higher crystallization temperature ($200^{\circ}C$) than that of the ITO films ($170^{\circ}C$), which was attributed to both larger ionic radius of $Yb^{3+}$ and higher bond enthalpy of $Yb_2O_3$, compared to ITO. This amorphous ITO:Yb film post-annealed at $170^{\circ}C$ showed a resistivity of $5.52{\times}10^{-4}{\Omega}cm$, indicating that a introduction of Yb increased resistivity of the ITO film. However, these amorphous ITO:Yb films showed a high etching rate, fine pattering property, and a very smooth surface morphology above the crystallization temperature of the amorphous ITO films (about $170^{\circ}C$). The transmittance of all films was >80% in the visible region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.171-172
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• 2008

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$ (BSCT) thick films doped with 0.1 mol% $MnCO_3$ and $Yb_2O_3$ ($0.1{\sim}0.7$ mol%) were fabricated by the screen printing method on the alumina substrate. And the structural and electrical properties as a function of $Yb_2O_3$ amount were investigated. The lattice constants of the BSCT thick film doped with 0.1 mol% is 0.3955 nm. The specimen doped with 0.7 mol% $Yb_2O_3$ showed dense and uniform grains with diameters of about 6.3 mm. The thickness of all BSCT thick films was approximately 60 mm. The Curie temperature of the BSCT specimen doped with 0.1 mol% $Yb_2O_3$ was $18^{\circ}C$, and the dielectric constantand dielectric loss at this temperature was 4637 and 4.2%, respectively. The BSCT specimen doped with 0.1 mol% $Yb_2O_3$ showed the maximum value of $349{\times}10^{-9}C/cm^2K$ at Curie temperature. The figure of merit $F_D$ for specific detectivity of the specimens doped with 0.1 mol% $Yb_2O_3$ showed the highest value of $10.9{\times}10^{-9}Ccm/J$.

• 한국초전도ㆍ저온공학회논문지
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• 제6권3호
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• pp.16-20
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• 2004

YB $a_2$C $u_3$$O_{7-x}$ (YBCO) films were deposited on (100) SrTi $O_3$ single crystal substrates by a metal organic chemical vapor deposition (MOCVD) system of hot-wall type using single liquid source. Under the condition of the mole ratio of Y(tmhd)$_3$:Ba(tmhd)$_2$:Cu(tmhd)$_2$= 1:2.1:2.9. the deposition pressure of 10 Torr. the MO source line speed of 15 cm/min. the Ar/ $O_2$ flow rate of 800/800 sccm. YBCO films were prepared at the deposition temperatures of 780∼89$0^{\circ}C$. In case of the YBCO films with 2.2 ${\mu}{\textrm}{m}$ thickness deposited for 6 minutes at 86$0^{\circ}C$. XRD pattern showed complete c-axis growth and SEM morphology showed dense and crack-free surface. The atomic ratios of Ba/Y and Cu/Ba in the film were 1.92 and 1.56. respectively. The deposition rate of the film was as high as 0.37 ${\mu}{\textrm}{m}$/min. The critical temperature ( $T_{c.zero}$) of the film was 87K. The critical current of the film was 104 A/cm-width. and the critical current density was 0.47 MA/$\textrm{cm}^2$. For the thinner film of 1.3 ${\mu}{\textrm}{m}$ thickness. the critical current density of 0.62 MA/$\textrm{cm}^2$ was obtained.d.

• E2M - 전기 전자와 첨단 소재
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• 제7권4호
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• pp.289-293
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• 1994

Thin films of YB $a_{2}$C $u_{3}$$O_{7-x}$ supercondYB $a_{2}$C $u_{3}$$O_{7-x}$uctor were prepared on (100) SrTi $O_{3}$ substrates by pulsed laser deposition using visible light laser. Q-switched Nd:YAG(532 nm, 30 ns) pulsed laser was used for deposition. The effects of substrate temperature and oxygen pressure during deposition on films were studied. Critical current density of 2.93*10$^{6}$ A/c $m^{2}$ at 77K and Tc(zero)=91.7K were obtained from the film prepared with Tsub=745.deg. C and $P_{02}$=200 mTorr. XRD analysis showed that the grown film has c-axis normal orientation to the substrate surface and has single phase. Surface morphology of the film has been improved by interfering the plume ejected from YB $a_{2}$C $u_{3}$$O_{7-x}$ target.arget.t.

• Transactions on Electrical and Electronic Materials
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• 제8권4호
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• pp.149-152
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• 2007

[ $(Ba_{0.6}Sr_{0.3}Ca_{0.1})TiO_3$ ](BSCT) thick films doped with 0.1 mol% $MnCO_3\;and\;Yb_2O_3(0.1{\sim}0.7mol%)$ were fabricated by the screen printing method on the alumina substrates. And the structural and electrical properties as a function of $Yb_2O_3$ amount were investigated. The exothermic peak was observed at around $680^{\circ}C$ due to the formation of the poly crystalline perovskite phase. The lattice constants of the BSCT thick film doped with 0.7 mol% is 0.3994 nm. The specimen doped with 0.7 mol% $Yb_2O_3$ showed dense and uniform grains with diameters of about $4.2{\mu}m$. The average thickness of all BSCT thick films was approximately $70{\mu}m$. Relative dielectric constant and dielectric loss of the specimen doped with 0.7 mol% $Yb_2O_3$ were 2823 and 3.4%, respectively. The Curie temperature of the BSCT thick films doped with 0.1 mol% $Yb_2O_3$ was $46^{\circ}C$.

• 한국세라믹학회지
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• 제41권2호
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• pp.170-175
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• 2004

Y-acetate, Yb-acetate와 Mn-acetate를 출발물질로 사용하여 sol-gel 법으로 강유전성 (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ 박막을 제조하였다. Acetylaceton을 촉매로 사용하고 Reflux 법을 이용하여 안정한 (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ 전구체 용액을 얻었으며, 박막은 스핀 코팅방법으로 Si(100) 기판 위에 제조하였다 열처리 온도, 코팅용액의 Rw($H_2O$/alkoxide moi ratio)변화 등을 실험변수로 하여 박막의 결정상 변화를 연구하였다. X-선 회절분석 결과 YbMn $O_3$의 결정상을 얻기 위한 최저 열처리온도는 7$50^{\circ}C$이었으며, 최적 열처리 조건은 80$0^{\circ}C$였다 Rw를 1∼6 범위 내에서 조절하여 첨가한 결과, Rw=1의 조건에서 c-축 배향이 잘 발달된 hexagonal YbMn $O_3$ 단일 결정상을 얻었다. Si(100)기판 위에 제조된 (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ 박막은 x=0 또는 1인 경우 잔류분극(Pr)값이 약 200 nC/$ extrm{cm}^2$을 나타내었으나 0

• 한국결정성장학회지
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• 제25권2호
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• pp.68-73
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• 2015

$Yb^{3+}$ 이온이 25 at.%까지 치환된 $Y_3Al_5O_{12}$ 단결정을 Czochralski 법으로 성장시켰다. 0.8 mm/h의 인상속도와 10 rpm의 회전 속도로 40 mm의 결정 직경과 160 mm의 결정 길이를 가진 단결정을 얻었다. 결정 성장 분위기는 순수한 질 소 혹은 질소와 산소를 혼합한 가스 분위기였다. 순수한 질소 분위기에서는 청록색을 띤 결정이 성장되었고 99 %의 질소와 1 %의 산소를 혼합한 가스 분위기에서 성장한 결정은 무색이었다. 농도 분석결과를 보면, 결정의 길이가 길어짐에 따라 $Yb^{3+}$의 농도는 감소하고, core 영역의 $Yb^{3+}$ 농도는 core 없는 영역보다 다소 높게 검출되었다. $Yb^{3+}$ 이온의 도핑 농도가 증가함에 따라 형광 수명은 감소하였다.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.581-586
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• 2007

[ $(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$ ] (BSCT) powders, prepared by sol-gel method, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen printing method. The structural and dielectric properties were investigated as a function of the $Yb_2O_3$ doping contents. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films showed the typical XRD patterns of a cubic polycrystalline structure. The average thickness of all BSCT thick films was about $70{\mu}m$. The grain size of the BSCT thick film doped with 0.7 mol% $Yb_2O_3$ was approximately $6.2{\mu}m$. The Curie temperature and relative dielectric constant at room temperature decreased with increasing $Yb_2O_3$ amount. Relative dielectric constant and dielectric loss of the specimen doped with 0.1 mol% $Yb_2O_3$ were 4637 and 19 % at Curie temperature, respectively.