• Title/Summary/Keyword: $YBa_2Cu_3O_{7-x}$ film

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Substrate effects on the characteristics of $YBa_2Cu_3O_{7-x}$ thin films prepared by RF magnetron sputtering (RF마그네트론 스퍼터링법으로 제조한 $YBa_2Cu_3O_{7-x}$전도체 박막의 특성에 대한 기판의 영향)

  • 신현용;박창엽
    • Electrical & Electronic Materials
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    • v.8 no.1
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    • pp.6-12
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    • 1995
  • High Tc superconducting YBa$_{2}$Cu$_{3}$$O_{7-x}$ thin films were prepared on various substrates by off-axis rf magnetron sputtering method to examine the substrate effects on the film structure and its R-T characteristics. The SEM analysis showed that the surface morphology of the grown YBa$_{2}$Cu$_{3}$O.sub 7-x/, film has different characteristic structure with different substrate used. The film on (100) SrTiO$_{3}$ substrate has critical current density of 3*10$^{5}$ A/cm$^{2}$ at 77K under zero magnetic field. The X-ray diffraction measurements revealed that the films on (100) SrTiO$_{3}$ substrate have mixed a-axis and c-axis normal to the substrate surface and the films on (100) MgO and ZrO$_{2}$/sapphire substrates have c-axis normal orientation to the substrate surface. However, YBa$_{2}$Cu$_{3}$$O_{7-x}$ films on (100) sapphire substrates showed no preferential orientation.ion.

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Crystalline Phases and Superconductor Characteristics of the Plasma Sprayed YBa2Cu$\chi$O7-y High Tc Superconductor Thick Film (플라즈마 용사법에 의해 제조된 YBa2Cu$\chi$O7-y(X=3, 3.5, 4) 고온초전도체 후막층의 결정상 및 초전도 특성)

  • 한명섭;서동수
    • Journal of the Korean Ceramic Society
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    • v.29 no.2
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    • pp.152-160
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    • 1992
  • High-Tc superconductor thick films of YBa2Cu$\chi$O7-y (X=3, 3.5, 4) of which thickness varies from 100 $\mu\textrm{m}$ to 200 $\mu\textrm{m}$ were successfully prepared by plasma spraying method, and the characteristics of thick film depending on copper content and heat treatment conditions were investigated. Regardless of heat-treated temperature, the specimens with X=3 were composed of YBa2Cu$\chi$O7-y, Y2BaCuO5 and BaCuO3 phases. The specimens with X=4, however, were composed of YBa2Cu$\chi$O7-y phase at all heat treatment conditions. The specimens with X=4 composition showed the best superconducting characteristics after heat treatment at 925$^{\circ}C$, and the superconducting transition temperature with zero resistivity (Tc,zero) was 87K. The thick film lost superconductivity when the specimens were heat-treated at 950$^{\circ}C$ because of interdiffusion between superconductor elements and bond coating elements and Y2BaCuO5 phase was found was found to be main phase at the interface.

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Fabrication and Electrical Properities of Semiconducting YBa2Cu3O7-x thin Film or Application of IR Sensors (적외선 센서로의 응용을 위한 반도성 YBa2Cu3O7-x 박막의 제작 및 전기적 특성)

  • Jeong, Jae-Woon;Jo, Seo-Hyeon;Lee, Sung-Gap
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.9
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    • pp.1296-1299
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    • 2012
  • $YBa_2Cu_3O_{7-x}$ thin films were fabricated by the spin-coating method on $SiO_2$/Si substrate using an alkoxide-based sol-gel method. The structural and electrical properties were investigated for various 1st annealing temperature. Due to the formation of the polycrystalline single phase, synthesis temperature was observed at around $720^{\circ}C-800^{\circ}C$. $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $450^{\circ}C{\sim}500^{\circ}C$ showed the single XRD patterns without the second phase, such as $YBa_2Cu_4O_8$. The thickness of films was approximately $0.23{\mu}m{\sim}0.27{\mu}m$. Aerage grain size, resistance and temperature coefficient of resistance (TCR) of $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $500^{\circ}C$ were $0.27{\mu}m$, $59.7M{\Omega}$ and -3.7 %/K, respecvitely.

Fabrication of the in-plane Aligned a-Axis Oriented $YBa_2Cu_3O_{7-x}$ Thin Films (평면배향된 a-축 수직 $YBa_2Cu_3O_{7-x}$ 고온초전도 박막의 제작)

  • 성건용;서정대
    • Journal of the Korean Ceramic Society
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    • v.33 no.3
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    • pp.313-320
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    • 1996
  • We have fabricated an in-plane aligned a-axis oriented YBa2Cu3O7-x (a-YBCO) thin film on a LaSrGaO4(100) substrate with a PrBa2Cu3O7-x(PBCO) template layer by two step plused laser deposition using 308 nm XeCl excimer laser. A YBCO layer and PBCO layer grown at low temperatures were used as template layers. We have investigated the effect of the deposition temperature of template layers on the superconducting and struc-tural properties of in-plane aligned a-YBCO thin films. An optimal deposition temperature of the PBCO template layers was 630. In-plane aligned a-YBCO thin films showed an anisotropy ratio in resistivity of 11.5 and a zero resistance temperature of 88 K.

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Formation of $YBa_2Cu_3O_7-\chi$ Superconducting Film on (100) MgO Substrate by a Spray Pyrolysis Method (용액분무법으로 MgO (100) 면에 제조한 $YBa_2Cu_3O_7-\chi$초전도)

  • 서동주;김건호
    • Journal of the Korean Vacuum Society
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    • v.1 no.3
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    • pp.389-394
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    • 1992
  • 용액분무법으로 (100) MgO 단결정 기판위에 YBa2Cu3O7-x 초전도박막을 제조하 였다. YBa2Cu3O7-x 초전도 박막의 Y, Ba, Cu 원자의 상대적인 비는 EDX의 검출 한계내에 서 1 : 2 : 3이었고, 이는 분무 용액속의 금속이온의 비와 같았다. YBa2Cu3O7-x 초전도 박 막의 결정구조는 단일 상의 사방구조였으며, 기판에 수직인 c축의 방향으로 grain이 성장되 었고, 격자상수 c0는 11.678$\AA$였다. 95$0^{\circ}C$의 공기중에서 10분간 열처리한 박막의 Tc-on=100K, Tc-zero=80K, Jc=2.5 $\times$ 104A/cm2였고, 95$0^{\circ}C$의 흐르는 산소분위기에서 10분간 열처리한 박막의 Tc-on=103K, Tc-zero=80K, Jc=1.0 $\times$ 105A/cm2였다. 초전도 박막의 미세구 조, grain 크기와 grain 경계폭은 제조후 열처리(post-annealing) 시간과 가스 분위기에 강 한 영향을 받았다.

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EPD Superconductor Film with Submicron YBCO on Ag Alloy

  • Soh, Dea-Wha;Fan, Zhanguo;Jeon, Yong-Woo
    • Journal of the Speleological Society of Korea
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    • no.76
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    • pp.49-55
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    • 2006
  • The submicron $YBa_2Cu_3O_x$ powder was prepared by the sol-gel method. The particle size is distributed from 0.2 to 1.0 ${\mu}m$, which benefits to eliminate the micro-cracks formed in the $YBa_2Cu_3O_x$ films deposited by electrophoresis. The powder was single phase of $YBa_2Cu_3O_x$ examined by X-ray diffraction. In the sol-gel process the citrate gel was formed from citric acid and nitrate solution of $Y_2O_3$, $Ba(NO_3)_2$ and CuO. When pH values were adjusted to 6.4-6.7, $Ba(NO_3)_2$ could be dissolved in the citrate solution completely. Appropriate evaporative temperature of the sol-gel formation is discussed. Acetone is used as electrophoreticsolution, in which some water and iodine (0.2 g/1) and polyethylene glycol (2 vol. %) are added. The concentrations of $YBa_2Cu_3O_x$ powders is 20g/l. The thickness of deposited film could be more than 50 ${\mu}m$ in 3 minutes of depositing time. The most EPD films could be 90K zero resistance and the Jc values were over 1000A/cm2 (0 H, 77 K).

Deposition conditions of $YBa_{2}$$Cu_{3}$$O_{7-x}$ deposited by a MOCVD method for coated conductors (MOCVD 법에 의해 증착 된 coated conductor용 $YBa_{2}$$Cu_{3}$$O_{7-x}$의 증착조건)

  • 선종원;전병혁;김찬중
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.83-86
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    • 2003
  • YBa$_2$Cu$_3$$O_{7-x}$ thin films for coated conductor application were deposited on a MgO single crystalline substrate by a metal organic chemical vapor deposition (MOCVD) system of a vertical type using a single liquid source. The film uniformity was enhanced by controlling the gas shower head structure, the distance between the shower head and substrate, and the rotation of the substrate. The source mole ratio of Y(thd)$_3$: Ba(thd)$_2$: Cu(thd)$_2$ was changed for obtaining stoichiometric film. The phase formation, crystal orientation, surface morphology and film composition were investigated with different source mole ratios, and the critical temperature (T$_{c}$) was measured.red.

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Epitaxial Growth of Pulsed-Laser Deposited Bi4Ti3O12/LaAlO3 Thin Films and Bi4Ti3O12/YBa2Cu3O7-x/LaAlO3 Heterostructure (펄스레이저 증착법으로 제작된 $Bi_4Ti_3O_{12}/LaAlO_3$ 박막과 $Bi_4Ti_3O_{12}/YBa_2Cu_3O_{7-x}/LaAlO_3$ 복합구조의 에피 성장)

  • Jo, Wol-Ryeom;Jo, Hak-Ju;No, Tae-Won
    • Korean Journal of Crystallography
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    • v.5 no.2
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    • pp.85-92
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    • 1994
  • Ferroelectric Bi4Ti3012 thin films have been grown on LaAlO(001) by Pulsed-laser deposition. Phase formation and structural films prepared of the films prepared at varigus deposition temperatures are investigated using x-ray diffraction The film grown at 740℃ shows epitaxial growth behavior with c-akis normal to the substrate. N2tBmstiucCures of Bi4Ti3012/YBa2Cu307-x/LaAIO3(001) have been in-situ grown. Even though the a-and b-axes of the Yba2Cu307-x layer show epitaxial growth behavior.

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A study of $YBa_2Cu_3O_{7-\delta}$ Thick Films by a Diffusion Process Between $Y-2BaCuO_5$ Substrate and ($BaCuO_2+CuO$) ($Y-2BaCuO_5$기판과 ($BaCuO_2+CuO$) 분말의 확산법에 의한 $YBa_2Cu_3O_{7-\delta}$ 후막 연구)

  • 조동언;임성훈;한태희;한병선
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.351-354
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    • 1998
  • The formation of the $YBa_2Cu_30_{7_\delta}$(Y123) thick films has been investigated by a surface diffusion Imcess between $3BaCu0_2$+2CuO composite coating powder and a $Y_2BaCuO_5$(Y211). This reaction has been studied in the temperature of $930^{\circ}C$ and $940^{\circ}C$ for 2h to 10h in an oxygen atmosphere. The Y211 substrates becomes covered by co-precipitation of Y123 grains and CuO inclusions. X-ray diflractotnctn. revealed that the lager consisted of an orthorhombic crystal structure. The maximum Jc of $400A/\textrm{cm}^2$ is abtained when the specimen was heat-treated at $930^{\circ}C$ for 6h on the Y211 substrate.

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High-rate growth $YBa_2$$Cu_3$$O_{7-x}$ thick films and thickness dependence of critical current density (Y$Ba_2$$Cu_3$$O_{7-x}$ 후막의 고속 증착과 임계 전류 밀도의 두께 의존성)

  • Jo W.
    • Progress in Superconductivity
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    • v.6 no.1
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    • pp.13-18
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    • 2004
  • High-.ate in-situ$ YBa_2$Cu$Cu_3$$O_{7-x}$ (YBCO) film growth was demonstrated by means of the electron beam co-evaporation. Even though our oxygen pressure is low, ∼$5 ${\times}$10^{-5}$ Torr, we can synthesize as-grown superconducting YBCO films at a deposition rate of around 10 nm/s. Relatively high temperatures of around 90$0^{\circ}C$ was necessary in this process so far, and it suggests that this temperature at a given oxygen activity allows a Ba-Cu-O liquid formation along with an YBCO epitaxy. Local critical current density shows a clear correlation with local resistivity. Homogeneous transport properties with a large critical current density ($4 ∼ 5 MA/\textrm{cm}^2$ at 77K, 0T) are observed in top faulted region while it is found that the bottom part carries little supercurrent with a large local resistivity. Therefore, it is possible that thickness dependence of critical current density is closely related with a topological variation of good superconducting paths and/or grains in the film bodies. The information derived from it may be useful in the characterization and optimization of superconducting films for electrical power and other applications.

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