• Title/Summary/Keyword: $YBa_2Cu_3O_x film

Search Result 98, Processing Time 0.029 seconds

YBa$_2$Cu$_3$O$_{7-x}$films fabricated on IBAD templates by MOCVD process (MOCVD 공정으로 IBAD 템플릿 위에 제조된 YBa$_2$Cu$_3$O$_{7-x}$ 박막)

  • Jun Byung-Hyuk;Choi Jun-Kyu;Kim Ho-Jin;Kim Chan-Joong
    • Progress in Superconductivity and Cryogenics
    • /
    • v.6 no.3
    • /
    • pp.21-26
    • /
    • 2004
  • Deposition condition of YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) films on moving IBAD templates (CeO$_2$/IBAD-YSZ/SS) was studied in a hot-wall type metal organic chemical vapor deposition (MOCVD) process using single liquid source. The reel velocity was 40 cm/hr and the source mole ratios of Y(tmhd)$_3$:Ba(tmhd)$_2$:Cu(tmhd)$_2$ were 1:2.3:3.1 and 1:2.1:2,9, Two different types of IBAD templates with thin CeO$_2$ and thick CeO$_2$ layers were used, The YBCO films were successfully deposited at the deposition temperatures of 780~89$0^{\circ}C$ ; the a-axis growth was observed together with the c-axis growth up to 83$0^{\circ}C$. while the c-axis growth became dominant above 83$0^{\circ}C$. The top surface of the c-axis film was fairly dense and included a small amount of the a-axis growth, although the peaks of the a-axis grains were not observed in XRD pattern, The YBCO film deposited on IBAD template with thin CeO$_2$ layer showed low critical current of 2.5 A/cm-width. while the YBCO film deposited on IBAD template with thick CeO$_2$ layer showed higher critical current of 50 A/cm-width. This result indicates that thick CeO$_2$ layer is thermally more stable than thin CeO$_2$ layer at the high deposition temperature of the MOCVD process.s.

Synthesis and Structural Properties of YBa2Cu3O7-x Films/ZnO Nanorods on SrTiO3 Substrates

  • Jin, Zhenlan;Park, C.I.;Song, K.J.;Han, S.W.
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2012.08a
    • /
    • pp.169-169
    • /
    • 2012
  • The high-temperature superconductor YBa2Cu3O7-x (YBCO) have attached attentions because of a high superconducting transition temperature, low surface resistance, high superconducting critical current density (Jc), and superior superconducting capability under magnetic field. Moreover, the Jc of YBCO superconductors can be enhanced by adding impurities to the YBCO films for vortex-pinning. Understanding and controlling pinning centers are key factors to realize high Jc superconductors. We synthesized vertically-aligned ZnO nanorods on SrTiO3 (STO) substrates by catalyst-free metal-organic chemical vapor deposition (MOCVD), and subsequently, deposited YBCO films on the ZnO nanorods/STO templates using pulsed laser deposition (PLD). The various techniques were used to analyze the structural and interfacial properties of the YBCO/ZnO nanorods/STO hybrid structures. SEM, TEM, and XRD measurements demonstrated that YBCO films on ZnO nanorods/STO were well crystallized with the (001) orientation. EXAFS measurements from YBCO/ZnO nanorods/STO at Cu K edge demonstrated that the local structural properties around Cu atoms in YBCO were quite similar to those of YBCO/STO.

  • PDF

Effect of $Y_2O_3$ Nanoparticles on Critical Current Density of $YBa_2Cu_3O_{7-x}$ Thin Films ($Y_2O_3$ 나노입자가 $YBa_2Cu_3O_{7-x}$ 박막의 임계전류밀도에 미치는 영향)

  • Tran, H.D.;Reddy, D.Sreekantha;Wie, C.H.;Kang, B.;Oh, Sang-Jun;Lee, Sung-Ik
    • Progress in Superconductivity
    • /
    • v.11 no.1
    • /
    • pp.62-66
    • /
    • 2009
  • 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.

  • PDF

Properties of $YBa_2{Cu_3}O_{7-X}$ superconducting thin films prepared by visible light pulsed laser (기사광선 펄스 레이저에 의해 제작된 $YBa_2{Cu_3}O_{7-X}$초전도체 박막의 특성)

  • 신현용
    • Electrical & Electronic Materials
    • /
    • v.7 no.4
    • /
    • pp.289-293
    • /
    • 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.

  • PDF

Characterization of Screen Printed $YBa_2Cu_3O_x$ Thick Films (스크린 프린팅법으로 제조된 $YBa_2Cu_3O_x$ 초전도 후막의 특성)

  • 김태윤;김승구;김대준;현상훈;정형진
    • Journal of the Korean Ceramic Society
    • /
    • v.30 no.12
    • /
    • pp.1007-1014
    • /
    • 1993
  • YBa2Cu3Ox(YBCO) thick films were prepared by a screen printing of the powders, obtained by a coprecipitation in oxalic acid, on the Y2O3-stabilized zirconia substrates and their superconducting properties were determined. TC, JC and the orientation factor of the thick films increased with increasing temperature up to 103$0^{\circ}C$ and then the superconducting properties disappeared with further heat treatments. The optimization of JC was achieved by heating thick films at 103$0^{\circ}C$ for 7min. In this case the TC of the thick film was determined to be 87.5K. It was observed that TC of thick films depends on the orthorhombicity and JC is likely governed by a microstructure of YBCO rather than by the orientation factor.

  • PDF

Effects of Excess Yttrium Addition on YBCO Thin Films Prepared by TFA-MOD Process (MOD-TFA 공정에 의한 YBCO박막제조시 과잉 yttrium첨가 효과에 관한 연구)

  • Lee Seung-Yi;Song Seul-A;Kim Byeong-Joo;Park Jin-A;Kim Ho-Jin;Lee Hee-Gyoun;Hong Gye-Won;Jang Seog Heon;Joo Jinho;Yoo Jai-Moo;Pradeep Halder
    • Progress in Superconductivity
    • /
    • v.7 no.1
    • /
    • pp.87-91
    • /
    • 2005
  • [ $YBa_{2}Cu_{3}O_{7-x}$ ] thin films were fabricated on $LaAlO_3$(100) substrate by TFA-MOD process. Yttrium-excess (0, 2.5, 5, 10, 15, 20 $at\%$) coating solution was prepared by adding extra amount of yttrium into a stoichiometric(Y:Ba:Cu=1:2:3) TFA precursor solution. Results are presented concerning the influence of excess yttrium additions on the microstructure development and superconducting properties of $YBa_{2}Cu_{3}O_{7-x}$ film. Large sized CuO particles was observed by SEM EDS investigation. The addition of excess yttrium affected little on $T_c$ of $YBa_{2}Cu_{3}O_{7-x}$ film. $J_c$ of YBCO film was enhanced with excess yttrium addition. Jc maximum of $2.21\;MA/cm^2$ (77 K, self field) appeared with the $15\;at\%$ addition of excess yttrium. With further yttrium addition up to $20\;at\%$, Jc decreased down to $0.9\;MA/cm^2$.

  • PDF

Electronic structure of $CaRuO_3$ (CRO) for buffer layer between superconductor and metal substrates (초전도체 $YBa_2Cu_3O_{7-X}$(YBCO)와 금속 기판사이의 계면 문제 해결을 위한 $CaRuO_3$ (CRO)의 전자 상태 계산)

  • 백한종;김양수;노광수
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2003.11a
    • /
    • pp.217-217
    • /
    • 2003
  • 초전도체 선재를 제작하기위해 YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) 와 Ni substrates사이의 계면 문제를 해결하기 위한 buffer layer로써 CaRuO$_3$ (CRO) thu film이 제안되었는데, 이런 buffer layer의 조건으로는Ni metal과 YBCO superconductor사이의 화학적 반응이 없어야 하고 metal component가 YBCO로 diffusion되는 것을 막아주어야 하며 substrates의 산화를 막아주어야 한다. 이런 조건을 만족시키는 것 중에서 CRO thin film이 가장 적절하였지만, CRO의 orthorhombic구조의 distortion에 의만 lattice mismatch 문제가 발생하였다. 이러한 문제를 해결하기 위해 이론적인 구조 분석을 통한 CRO의superconductor buffer layer로써의 가능성을 검토해 보는 것이 목적이다.

  • PDF

Crystalline Qualities and Surface Morphologies of As-Grown $YBa_2Cu_3O_{7-x}$ Thin Films on MgO(100) Substrate by Reactive Coevaporation Method (반응성 동시 증착법에 의한 As-grown $YBa_2Cu_3O_{7-x}$ 박막의 결정 특성 및 표면형상에 관한 연구)

  • Jang, Ho-Yeon;Watanabe, Yasuhiro;Doshida, Yutaka;Shimizu, Kenji;Okamoto, Yoichi;Akibama, Ryozo;Song, Jin-Tae
    • Korean Journal of Materials Research
    • /
    • v.1 no.2
    • /
    • pp.93-98
    • /
    • 1991
  • The as-grown $YBa_2Cu_3O_{7-x}$ superconducting thin films on MgO(100) substrate have been prepared by a reactive coevaporation method. The superconducting transition temperature, surface morphology and crystalline quality were examined as a function of the substrate temperature ranging from $450^{\circ}C$ to $590^{\circ}C$. From the reflection high energy electron diffraction (RHEED) analysis, it was found the film consisted of almost amorphous phase with a halo pattern deposited at the substrate temperature of $450^{\circ}C$. The film deposited at the substrate temperature of $510^{\circ}C$ consisted of polycrystalline phase, showing a broad ring pattern. On the other hand, for the film deposited at $590^{\circ}C$, RHEED showed spotty pattern indicating that this film consisted of single crystal phase. It has rough film surface due to the surface outgrowth. The surface outgrowth increased as the substrate temperature increased from $510^{\circ}C$ to $590^{\circ}C$. the surface outgrowth may be due to the anisotropic growth rate. The highest transition temperature obtained in this study was $Tc_{zero}$ of 83K with $Tc_{onset}$ of 88K for the film deposited at $590^{\circ}C$ using activated RF oxygen plasma.

  • PDF

The preparation of $YBa_2Cu_3O_x$ superconducting thin film using rf - magnetron sputtering system (Rf - magnetron sputtering system을 사용한 $YBa_2Cu_3O_x$ 초전도 박막의 제조)

  • Park, S.J.;Kim, M.K.;Choi, S.H.;Choi, H.S.;Hwang, J.S.;Han, B.S.
    • Proceedings of the KIEE Conference
    • /
    • 1992.07b
    • /
    • pp.717-720
    • /
    • 1992
  • Since the discovery of High-Tc superconducting Y-Ba-Cu-O ceramics with critical temperature of about 90K, numerous efforts to prepare supercond ucting thin films with excellent qualities such as High-Tc and critical current density have been made. The samples were deposited onto $SiO_x$ substrates heated at 540$^{\circ}C$ - 600$^{\circ}C$ in a single target rf - magnetron sputtering system. The film thickness has 2000$\AA$ - 5000 $\AA$ with a rate of 16 $\AA$/min. and distance between target and substrate was 50 mm. The films were characterized by X - ray diffraction, scanning electron microscopy and critical temperature.

  • PDF