• E2M - 전기 전자와 첨단 소재
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• 제8권3호
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• pp.285-290
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• 1995

High quality $Y_{1}$Ba$_{2}$Cu$_{3}$$O_{7-x}$ thin films have been fabricated by pulsed Nd:YAG laser deposition using an unusual 'off-axis' target-substrate geometry. Various properties of superconducting $Y_{1}$Ba$_{2}$Cu$_{3}$$O_{7-x}$ thin films have been studied systematically as a function of oxygen pressure during the deposition, in both 'on-axis' and the unusual 'off-axis' target substrate geometries. In the 'off-axis' geometry, one can completely eliminate the so-called 'laser droplets' from the film surface and thus obtain smooth high quality films. It is found that films with optimum structural and electrical properties are obtained at a lower oxygen pressure range during the 'off-axis' deposition when compared with that required in the 'on-axis' deposition geometry.

• 한국세라믹학회지
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• 제33권3호
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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.

• 한국자기학회지
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• 제4권1호
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• pp.44-47
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• 1994

Laser ablation법으로 c-축 배향되도록 만든 Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7- .delta. / 박막으로 임계온도 근처에서 운반자들의 정보를 얻기위하여 Hall 효과를 연구하였다. 자기비저항은 Nernst 효과 때문에 자기장이 증가할 수록 offset 점의 온도가 낮았고, 자기비저항으로 부터 열자기적 효과를 고 려하여 계산한 Hall 비저항값과 실제 van der Pauw 법으로 측정한 Hall 비저항값을 비교해 본 결과 비교적 잘 일치하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.148-151
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• 1995

Excimer laser has been used to fabricate superconducting YBa$_2$Cu$_3$O$\sub$7-x/(YBCO) thin films on various substrates. An XeCl excimer laser with an wavelength of 308 nm was used to deposit both buffer layer and superconducting thin film on sapphire substrate. The characterizations of the interface between thin film and substrate were performed. The interfacial properties of thin films on buffered sapphire and on bare sapphire were compared. With a 20 nm PrBa$_2$Cu$_3$O$\sub$7-x/(PBCO) buffer layer, no diffusion layer was observed between film and substrate while the diffusion layer with about 30 nm thickness was observed between film and sapphire without buffer layer.

• 한국초전도ㆍ저온공학회논문지
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• 제18권4호
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• pp.1-4
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• 2016

We investigated the relation between the Cu-O bond length and the superconducting properties of $BaSnO_3$ (BSO)-added $GdBa_2Cu_3O_{7-x}$ (GdBCO) thin films by using extended x-ray absorption fine structure (EXAFS) spectroscopy. 4 wt.% $BaSnO_3$ (BSO) added $GdBa_2Cu_3O_{7-x}$ (GdBCO) thin films with varying thickness from $0.2{\mu}m$ to $1.0{\mu}m$ were fabricated by using pulsed laser deposition (PLD) method. The transition temperature ($T_c$) and the residual resistance ratio (RRR) of the GdBCO films increased with increasing thickness up to $0.8{\mu}m$, where the crystalline BSO has the highest peak intensity, and then decreased. This uncommon behaviors of $T_c$ and RRR are likely to be created by the addition of BSO, which may change the ordering of GdBCO atomic bonds. Analysis from the Cu K-edge EXAFS spectroscopy showed an interesting thickness dependence of ordering behavior of BSO-added GdBCO films. It is noticeable that the ordering of Cu-O bond and the transition temperature are found to show opposite behaviors in the thickness dependence. Based on these results, the growth of BSO seemingly have evident effect on the alteration of the local structure of GdBCO film.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.362-363
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• 2006

In this study, the filter was designed for tuning center frequency and fabricated using ($Sr,Ba)TiO_3$ ferroelectrics and $YBa_2CuO_7$ high temperature superconductor thin film. The best result in figure of merit was 35 when the $Ba_{0.5}Sr_{0.5}TiO_3$ thin film deposition temperature was $600^{\circ}C$, the post anneal condition was $600^{\circ}C$, 10min in 1atm, $O_2$. When using $20{\mu}m$ IDC pattern gap. The higher tunability was obtained than using $30{\mu}m$ pattern gap.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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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.

• 한국전기전자재료학회논문지
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• 제13권11호
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• pp.959-962
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• 2000

We have fabricated good quality superconducting YBa$_2$Cu$_3$$O_{7-x}$(YBCO) thin films on Hastelloy(Ni-Cr-Mo alloys) metallic substrates with CeO$_2$and BaTiO$_3$buffer layers in-situ by pulsed laser deposition in a multi-target processing chamber. YBCO film with CeO$_2$single buffer layer shows T$_{c}$ of 71.64 K and the grain size less than 0.1${\mu}{\textrm}{m}$. When BaTiO$_3$ is used as a single buffer layer, the grain size of YBCO is observed to be larger than that of YBCO/CeO$_2$by 200 times and the transition temperature of the film is enhanced to be about 84 K. CeO$_2$/BaTiO$_3$double buffer layer has been adopted to enhance the superconducting properties, which results in the enhancement of the critical temperature and the critical current density to be about 85 K and 8.4$\times$10$^4$ A/$\textrm{cm}^2$ at 77 K, respectively mainly due to the enlargement of the grain size of YBCO film.ilm.

• ETRI Journal
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• 제18권4호
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• pp.339-346
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• 1997

Good quality a-axis oriented thin films of $YBa_2Cu_3O_{7-x}$ may be grown by the use of a $PrBa_2Cu_3O_{7-x}$ (PBCO) layer as a template. Here we present a detailed study of the nucleation of the PBCO layer, explaining the orientations observed. It is determined that the wavy surface of a $LaSrGaO_4$ (LSGO) (100) substrate consists of the {101} planes by observing cross-sectional transmission electron microscopy images of the interface between the PBCO film and the substrate. The images and selected area diffraction patterns show that a mixed c-and b-axis oriented PBCO layer was initially grown on the substrate, followed by pure b-axis oriented PBCO growth. We explain that the c-axis oriented growth is the result of the growth of the PBCO (019) planes on the LSGO (101) planes. We conclude that the nucleation and growth of the PBCO films at the initial stages depends on the crystallographic plane of the substrate surfaces, however, as the film grows further, the kinetics of the deposition process favors b-axis oriented growth.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.790-793
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• 2000

We have fabricated good quality superconducting YBa$_2$Cu$_3$$O_{7-x}$(YBCO) thin films on Hastelloy(Ni-Cr-Mo alloys) metallic substrates with CeO$_2$and BaTiO$_3$buffer layers in-situ by pulsed laser deposition in a multi-target processing chamber. YBCO film with CeO$_2$ single buffer layer shows T$_{c}$ of 71.64 K and the grain size less than 0.1 ${\mu}{\textrm}{m}$. When BaTiO$_3$is used as a single buffer layer, the grain size of YBCO is observed to be larger than that of YBCO/CeO$_2$by 200 times and the transition temperature of the film is enhanced to be about 84 K. CeO$_2$/BaTiO$_3$double buffer layer has been adopted to enhance the superconducting properties, which results in the enhancement of the critical temperature and the critical current density to be about 85 K and 8.4 $\times$ 10$^4$ A/cm$^2$ at 77 K, respectively mainly due to the enlargement of the grain size of YBCO film.ilm.