http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of $Y_2O_3$ Nanoparticles on Critical Current Density of $YBa_2Cu_3O_{7-x}$ Thin Films
위창환,강병원,오상준,이성익,Tran, H.D.,Reddy, D.Sreekantha,Wie, C.H.,Kang, B.,Oh, Sang-Jun,Lee, Sung-Ik 한국초전도학회 2009 Progress in superconductivity Vol.11 No.1
Introduction of proper impurity into $YBa_2Cu_3O_{7-x}$ (YBCO) thin films is an effective way to enhance its flux-pinning properties. We investigate effect of $Y_2O_3$ nanoparticles on the critical current density $J_c$ of the YBCO thin films. The $Y_2O_3$ nanoparticles were created perpendicular to the film surface (parallel with the c-axis) either between YBCO and substrate or on top of YBCO, YBCO/$Y_2O_3$/LAO or $Y_2O_3$/YBCO/STO, by pulsed laser deposition. The deposition temperature of the YBCO films were varied ($780^{\circ}C$ and $800^{\circ}C$) to modify surface morphology of the YBCO films. Surface morphology characterization revealed that the lower deposition temperature of $780^{\circ}C$ created nano-sized holes on the YBCO film surface which may behave as intrinsic pinning centers, while the higher deposition temperature produced much denser and smoother surface. $J_c$ values of the YBCO films with $Y_2O_3$ particles were either remained nearly the same or decreased for the samples in which YBCO is grown at $780^{\circ}C$. On the other hand, $J_c$ values were enhanced for the samples in which YBCO is grown at higher temperature of $800^{\circ}C$. The difference in the effect of $Y_2O_3$ can be explained by the fact that the higher deposition temperature of $800^{\circ}C$ reduces intrinsic pinning centers and $J_c$ is enhanced by introduction of artificial pinning centers in the form of $Y_2O_3$ nanoparticles.
YBCO 다층박막에 첨가된 $Y_2O_3$와 ZnO 나노입자의 자속꽂음 중심 특성 비교
위창환,강병원,김이정,오상준,이남훈,강원남,Wie, C.H.,Tran, D.H.,Putri, W.B.K.,Kang, B.,Kim, Y.J.,Oh, S.J.,Lee, N.H.,Kang, W.N. 한국초전도학회 2011 Progress in superconductivity Vol.13 No.2
We investigated the properties of artificial pinning centers of YBCO multilayer films in which $Y_2O_3$ and ZnO nanoparticles are uniformly introduced by using the pulsed laser deposition (PLD) technique. $Y_2O_3$ and ZnO nanoparticles were deposited on top of YBCO buffer layer and the density of nanoparticles was controlled by varying the number of nanoparticle layers. YBCO superconducting layers with total thickness of 250 nm were deposited on top of $Y_2O_3$ and ZnO nanoparticles. Based on analyses of the surface morphology, the transition temperature $T_c$, and the critical current density $J_c$, we discussed the difference between the two kinds of nanoparticles as flux pinning centers.
ZnO 나노입자 첨가에 의한 YBCO 다층 박막의 자속꽂음 특성 향상
위창환,D. H. Tran,W. B. K. Putri,강병원,이남훈,강원남,황태종,김동호 한국물리학회 2012 새물리 Vol.62 No.5
We investigated the critical current density of YBCO multilayer films in which ZnO nanoparticles had been uniformly embedded by using the pulsed laser ablation technique. The ZnO nanoparticles were deposited on a thin YBCO buffer layer perpendicular to the c-axis of the film. The density of nanoparticles was controlled by varying the number of nanoparticle layers, and YBCO superconducting layers with a total thickness of 250 nm were deposited on top of the ZnO nanoparticles. Based on analyses on the surface morphology, the transition temperature, and the critical current density, we discuss the possibility of ZnO nanoparticles serving as effective flux-pinning centers in magnetic fields. Pulsed Laser Deposition (PLD)를 사용하여 ZnO 나노입자를 YBCO 박막에다층구조로 균일하게 첨가하였을 때 YBCO 박막의 임계자속밀도(critical current density)를 연구하였다. SrTiO_3(STO) 기판위에 YBCO 완충층(buffer layer)을 c-축 방향(c-axis oriented)으로 증착하고,a-축 방향으로 성장한 ZnO 나노입자를 YBCO 완충층위에 고르게첨가하였다. ZnO 나노입자의 층수를 변화하여 나노입자의 밀도를조절하였고 YBCO 초전도 층은 총 박막 두께가 250 nm 로 일정하게증착하였다. 다층박막의 표면 구조, 임계온도 (T_c), 그리고 임계전류밀도 (J_c)의 분석 결과에 기초하여, ZnO 나노입자의 자기장에서효과적인 자속 꽂음 중심(flux pinning center)으로써의 가능성에 대해논의하였다.
Flux-pinning Properties of YBa2Cu3O7−x Multilayered Films with Y2O3 and ZnO Nanoparticle Inclusions
강병원,위창환,Duc Hai Tran,Witha Berlian Kesuma Putr,황태종,김동호 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.11
We investigated the flux-pinning properties of YBa2Cu3O7−x (YBCO) films in which Y2O3 and ZnO nanoparticles were uniformly embedded by using the pulsed laser deposition (PLD) technique. Y2O3 and ZnO nanoparticles with average sizes of 10–30 nm and with different densities by changing the number of nanoparticle layers were introduced in a YBCO matrix in the form of a multilayered structure. The total thickness of the YBCO superconducting layers was kept to be 250 nm. Dilute doping was found to be effective for both Y2O3 and ZnO nanoparticles. For Y2O3 doping, critical current density (Jc) enhancements over a wide range of fields were obtained in 1- and 5-layer doped samples, while weak Jc enhancements and a better field dependence of Jc were found in the YBCO film with 1 layer of ZnO. Based on an analysis of surface morphology, the transition temperature (Tc), and Jc, we discuss the difference between the two types of nanoparticles as flux-pinning centers.