http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Wang, X L,Dou, S X,Ren, Zhi-An,Yi, Wei,Li, Zheng-Cai,Zhao, Zhong-Xian,Lee, Sung-IK IOP Pub 2009 Journal of physics, an Institute of Physics journa Vol.21 No.20
<P>We measured the initial <I>M</I>–<I>H</I> curves for a sample of the newly discovered superconductor NdFeAsO<SUB>0.82</SUB>Fe<SUB>0.18</SUB>, which had a critical temperature, <I>T</I><SUB>c</SUB>, of 51 K and was fabricated at the high pressure of 6 GPa. The lower critical field, <I>H</I><SUB>c1</SUB>, was extracted from the deviation point of the Meissner linearity in the <I>M</I>–<I>H</I> curves, which show linear temperature dependence in the low temperature region down to 5 K. The <I>H</I><SUB>c1</SUB>(<I>T</I>) indicates no s-wave superconductivity, but rather an unconventional superconductivity with a nodal gap structure. Furthermore, the linearity of <I>H</I><SUB>c1</SUB> at low temperature does not hold at high temperature, but shows other characteristics, indicating that this superconductor might have multi-gap features. Based on the low temperature nodal gap structure, we estimate that the maximum gap magnitude Δ<SUB>0</SUB> = (1.6 ± 0.2) <I>k</I><SUB>B</SUB><I>T</I><SUB>c</SUB>.</P>
Fabrication of Magnesium Diboride Thin Films by Aerosol Deposition
Sinha, B.B.,Chung, K.C.,Jang, S.H.,Hahn, B.D.,Park, D.S.,Wang, X.L.,Dou, S.X. The Korean Superconductivity Society 2011 Progress in superconductivity Vol.13 No.2
Superconducting $MgB_2$ thin films were fabricated by using a novel aerosol deposition technique wherein the pre-reacted powder is directly transformed into respective thin film. The formed thin films were characterized by X-ray diffraction technique and FE-SEM to understand its structure and morphology and the superconducting behavior has been characterized with the four probe resistivity measurement. The as-deposited thin films were formed into the frustrated amorphous structure, which were relaxed on the further heat treatment at $900^{\circ}C$ for 3 hrs. The relaxed amorphous $MgB_2$ thin films showed a comparatively high superconducting onset at about 38 K.
Chung, K C,Yoo, J M,Kim, Y K,Wang, X L,Dou, S X IOP Publishing Ltd 2009 Superconductor science & technology Vol.22 No.2
<P>The influence of water pressure in the metal–organic deposition (MOD) method on the texture and morphology of YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7−<I>X</I></SUB> (YBCO) films grown on buffered metal substrates was investigated. The water pressure was varied from 4.2% to 10.0%, with the other process parameters, such as annealing temperature and oxygen pressure, kept constant. In this work, a YBCO precursor solution was prepared using a fluorine-free Y and Cu precursor solution with the addition of Sm. MOD-YBCO films were fabricated by continuous slot-die coating and calcination, followed by high temperature annealing. Using x-ray diffraction analysis, unreacted phase peaks, such as BaF<SUB>2</SUB> peaks, were found in the samples made at a water pressure of 4.2%; however, the BaF<SUB>2</SUB> peak intensity was much reduced as the water pressure was increased. The higher water pressure of about 10.0% in this experiment led to the poor crystallinity of MOD-YBCO films, possibly due to the fast reaction with the supplied water vapor. Meanwhile, the morphologies of the YBCO films were not much different from each other in the range of water pressure of this work. The maximum critical current density of 3.8 MA cm<SUP>−2</SUP> was obtained when the sample was made at the water pressure of 6.2% and the annealing temperature of 780 °C.</P>
Chung, Kook-Chae,Yoo, Jai-Moo,Ko, Jae-Woong,Kim, Young-Kuk,Wang, X.L.,Dou, S.X. The Korean Society of Superconductivity and Cryoge 2007 한국초전도저온공학회논문지 Vol.9 No.2
The influence of water partial pressure in Metal-organic Deposition (MOD) method was investigated on the texture and the morphology of $YBa_2Cu_3O_{7-x}$ (YBCO) films grown on the buffered metal tapes. The water partial pressure was varied from 4.2% up to 10.0% with the other process variables, such as annealing temperature and oxygen partial pressure, kept constant. In this work, the fluorine-free Y & Cu precursor solution added with Sm was synthesized and coated by the continuous slot-die coating & calcination step. The next annealing step of the YBCO films was done by the reel-to-reel method with the gas flowed vertically down. From the x-ray diffraction analysis, the un-reacted phase like $BaF_2$ peak was found at the water partial pressure of 4.2%, but $BaF_2$ peak intensity is much reduced as the water partial pressure is increased. However, the higher water partial pressure of about 10% in this experiment leads to the poor crystallinity of YBCO films. The morphologies of the YBCO films were not different from each other when the water partial pressure was varied in this work. The maximum critical current density of 3.8MA/$cm^2$ was obtained at the water partial pressure of 6.2% with the annealing temperature of 780$^{\circ}C$ and oxygen partial pressure of 500ppm.
RF-스퍼터링법을 이용하여 Ni-W 금속기판에 연속공정으로 증착된 Y2O3 완충층 특성 연구
정국채,정태정,최규채,김영국,X.L.Wang,S.X.Dou 한국초전도학회 2010 Progress in superconductivity Vol.11 No.2
Reel-to-reel deposition of Y2O3 has been performed on Ni-5%W metal substrates using the RF-sputtering method. The epitaxial orientation of Y2O3 buffer layers to the base bi-axially textured substrate was well identified using θ-2θ,out-of-plane (ω), and in-plane (φ) scans in X-ray diffraction analysis. The optimization of Y2O3 seed layers in reel-to-reel fashion were investigated varying the deposition temperature, sputtering power, and pressure for its significant roles for the following buffer stacks and superconducting layers. Y2O3 were all grown epitaxially on bi-axially textured metal substrates at 380 watts and 5 mTorr in the temperature range of 600-740 oC with higher Y2O3 (400) intensities at ~710 oC. It was found that the Δω values were 1-2o lower but the Δφ values were above 1o higher than that of Ni-W substrates. As the sputtering power increased from 340 to 380 watts, Δω and Δφ values showed decreased tendency. Even in the small window of deposition pressure of 3-7 mTorr, the Y2O3 (400) intensities increased and Δω and Δφ values were reduced as sputtering pressure increased.
Fabrication of Magnesium Diboride Thin Films by Aerosol Deposition
B.B.Sinha,정국채,장세훈,한병동,박동수,X. L. Wang,S. X. Dou 한국초전도학회 2011 Progress in superconductivity Vol.13 No.2
Superconducting MgB2 thin films were fabricated by using a novel aerosol deposition technique wherein the pre-reacted powder is directly transformed into respective thin film. The formed thin films were characterized by X-ray diffraction technique and FE-SEM to understand its structure and morphology and the superconducting behavior has been characterized with the four probe resistivity measurement. The as-deposited thin films were formed into the frustrated amorphous structure,which were relaxed on the further heat treatment at 900 °C for 3 hrs. The relaxed amorphous MgB2 thin films showed a comparatively high superconducting onset at about 38 K.
RF-스퍼터링법을 이용하여 Ni-W 금속기판에 연속공정으로 증착된 $Y_2O_3$ 완충층 특성 연구
Chung, K.C.,Jeong, T.J.,Choi, G.C.,Kim, Y.K.,Wang, X.L.,Dou, S.X. 한국초전도학회 2010 Progress in superconductivity Vol.11 No.2
Reel-to-reel deposition of $Y_2O_3$ has been performed on Ni-5%W metal substrates using the RF-sputtering method. The epitaxial orientation of $Y_2O_3$ buffer layers to the base bi-axially textured substrate was well identified using ${\theta}-2{\theta}$, out-of-plane ($\omega$), and in-plane ($\phi$) scans in X-ray diffraction analysis. The optimization of $Y_2O_3$ seed layers in reel-to-reel fashion were investigated varying the deposition temperature, sputtering power, and pressure for its significant roles for the following buffer stacks and superconducting layers. $Y_2O_3$ were all grown epitaxially on bi-axially textured metal substrates at 380 watts and 5 mTorr in the temperature range of $600-740^{\circ}C$ with higher $Y_2O_3$ (400) intensities at ${\sim}710^{\circ}C$. It was found that the $\Delta\omega$ values were $1-2^{\circ}$ lower but the $\Delta\phi$ values were above $1^{\circ}$ higher than that of Ni-W substrates. As the sputtering power increased from 340 to 380 watts, $\Delta\omega$ and $\Delta\phi$ values showed decreased tendency. Even in the small window of deposition pressure of 3-7 mTorr, the $Y_2O_3$ (400) intensities increased and $\Delta\omega$ and $\Delta\phi$ values were reduced as sputtering pressure increased.
Ghorbani, S R,Wang, X L,Hossain, M S A,Dou, S X,Lee, Sung-Ik IOP Publishing Ltd 2010 Superconductor science & technology Vol.23 No.2
<P>The flux pinning mechanisms of nano-Si-doped MgB<SUB>2</SUB> are reported in this work. The field dependence of the critical current density, <I>J</I><SUB>c</SUB>(<I>B</I>), was analyzed within the collective pinning model. We found that the mechanisms for both δ<I>l</I> pinning, i.e., pinning associated with charge-carrier mean free path fluctuations, and δ<I>T</I><SUB>c</SUB> pinning, which is associated with spatial fluctuations of the transition temperature, coexist in the nano-Si-doped MgB<SUB>2</SUB> samples, while <I>H</I><SUB>c2</SUB> increases greatly with increasing nano-Si doping level. However, their contributions are strongly temperature dependent. The δ<I>l</I> pinning is dominant at low temperatures, decreases with increasing temperature, and is suppressed completely at temperatures close to the critical temperature, <I>T</I><SUB>c</SUB>. However, the δ<I>T</I><SUB>c</SUB> pinning mechanism shows opposite trends. </P>
Fabrication of silver stabilization layer of coated conductor using organic silver complexes
Lee, J.B.,Park, S.J.,Kim, S.S.,Moon, S.H.,Lee, H.G.,Kim, J.H.,Dou, S.X.,Hong, G.W. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.20
Silver stabilizing layer of coated conductor has been prepared by dip coating method using organic silver complexes containing 10wt.% silver as a starting material. Coated silver complex layer was dried in situ with hot air and converted to crystalline silver by post heat treatment in flowing oxygen atmosphere. A dense continuous silver layer with good surface coverage and proper thickness of 230nm is obtained by multiple dip coatings and heat treatments. The film heat treated at 500<SUP>o</SUP>C showed good mechanical adhesion and crystallographic property. The interface resistivity between superconducting YBCO layer and silver layer prepared by dip coating was measured as 0.67x10<SUP>-13</SUP>Ωm<SUP>2</SUP>. Additional protecting copper layer with the thickness of 20μm was successfully deposited by electroplating. The critical current measured with the specimen prepared by dip coating and sputtering on same quality YBCO layer showed similar value of ~140A and proved its ability to replace sputtering method for industrial production of coated conductor.