• 제목/요약/키워드: superconducting thin films

검색결과 258건 처리시간 0.021초

에어로졸 증착법에 의한 $MgB_2$ 박막 제조 (Fabrication of Magnesium Diboride Thin Films by Aerosol Deposition)

  • ;정국채;장세훈;한병동;박동수
    • Progress in Superconductivity
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    • 제13권2호
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    • pp.122-126
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    • 2011
  • 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.

Line-shaped superconducting NbN thin film on a silicon oxide substrate

  • Kim, Jeong-Gyun;Suh, Dongseok;Kang, Haeyong
    • 한국초전도ㆍ저온공학회논문지
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    • 제20권4호
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    • pp.20-25
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    • 2018
  • Niobium nitride (NbN) superconducting thin films with the thickness of 100 and 400 nm have been deposited on the surfaces of silicon oxide/silicon substrates using a sputtering method. Their superconducting properties have been evaluated in terms of the transition temperature, critical magnetic field, and critical current density. In addition, the NbN films were patterned in a line with a width of $10{\mu}m$ by a reactive ion etching (RIE) process for their characterization. This study proves the applicability of the standard complementary metal-oxide-semiconductor (CMOS) process in the fabrication of superconducting thin films without considerable degradation of superconducting properties.

스퍼터링 방식에 의한 Y-Ba-Cu-O 고온 초전도 박박의 제작에 관한 연구 (A study on the fabrication of Y-Ba-Cu-O High Tc superconducting thin film by sputtering system)

  • 채기병;강기성;소대화
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1992년도 추계학술대회 논문집
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    • pp.81-83
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    • 1992
  • The superconducting thin films deposited on $SiO_x$ substrate by R.F magnetron sputter using $YBa_2Cu_3O_x$ single target have been made and annealed at $940^{\circ}C$ for 30 min. The thickness of films were 1000-2000${\AA}$ with a rate of 20-25${\AA}/min$ and superconducting properties of thin films depended on the compositions of pre-annealed the thin films. It has been analyzed by SEM photo-analysis and X-ray diffraction patterns of these samples obtained under the various conditions of this sputtering methods. and recognized the supperconducting thin films by electric properties.

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레이저 증착법을 이용한 금속기판상 고온초전도 박막증착 및 특성분석 (Fabrication and Characterization of High Temperature Superconducting Thin Film on Metallic Substrate Using Laser Ablation)

  • 이상렬
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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    • pp.329-331
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    • 1995
  • Laser ablation was used to fabricate superconducting $YBa_2Cu_3O_{7-x}$ (YBCO) thin films on metallic substrates with an YSZ buffer layer. An ArF excimer laser with an wavelength of 193 nm was used to deposit both YSZ buffer layer and superconducting thin film. The characterizations of thin films were performed and compared. With a 200 nm YSZ buffer layer, c-axis orientation and $T_c$=85 K were obtained for a 200 nm-thick YBCO film.

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HIGH TEMPERATURE SUPERCONDUCTING THIN FILMS PREP ARED BY PULSED LASER DEPOSITION

  • Park, Yong-Ki;Kim, In-Seon;Ha, Dong-Han;Hwang, Doo-Sup;Huh, Yun-Sung;Park, Jong-Chul
    • 한국표면공학회지
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    • 제29권5호
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    • pp.430-436
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    • 1996
  • We have grown superconducting thin films on various substrates using a pulsed laser deposition (PLD) method. $YBa_2Cu_3O_7-\delta$ (YBCO) superconducting thin films with the superconducting transition temperature ($T_{c. offset}$) of 87K were grown on Si substrates using yittria-stabilized zirconia (YSZ) and $CeO_2$ double buffer layers. We have developed a large area pulsed laser deposition system. The system was designed to deposit up to 6 different materials on a large area substrate up to 7.5cm in diameter without breaking a vacuum. The preliminary runs of the deposition of YBCO superconducting thin films on $SrTiO_3$ substrate using this system showed a very uniform thickness profile over the entire substrate holder area. $T_{c}$ of the deposited YBCO thin film, however, was scattered depending on the position and the highest value was 85K.

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Hall effect of K-doped $BaFe_2As_2$ superconducting thin films

  • Son, Eunseon;Lee, Nam Hoon;Hwang, Tae-Jong;Kim, Dong Ho;Kang, Won Nam
    • 한국초전도ㆍ저온공학회논문지
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    • 제15권3호
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    • pp.5-8
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    • 2013
  • We have studied Hall effect for potassium (K)-doped $BaFe_2As_2$ superconducting thin films by analyzing the relation between the longitudinal resistivity (${\rho}_{xx}$) and the Hall resistivity (${\rho}_{xy}$). The thin films used in this study were fabricated on $Al_2O_3$ (000l) substrates by using an ex-situ pulsed laser deposition (PLD) technique under a high-vacuum condition of ~$10^{-6}$ Torr. The samples showed the high superconducting transition temperatures ($T_c$) of ~ 40 K. The ${\rho}_{xx}$ and the ${\rho}_{xy}$ for K-doped $BaFe_2As_2$ thin films were measured by using a physical property measurement system (PPMS) with a temperature sweep (T-sweep) mode at an applied current density of $100A/cm^2$ and at magnetic fields from 0 up to 9 T. We report the T-sweep results of the ${\rho}_{xx}$and the ${\rho}_{xy}$ to investigate Hall scaling behavior on the basis of the relation of ${\rho}_{xy}={A{\rho}_{xx}}^{\beta}$. The ${\beta}$ values are $3.0{\pm}0.2$ in the c-axis-oriented K-doped $BaFe_2As_2$ thin films, whereas the thin films with various oriented-directions like a polycrystal showed slightly lower ${\beta}$ than that of c-axis-oriented thin films. Interestingly, the ${\beta}$ value is decreased with increasing magnetic fields.

스퍼터링 증착된 Y-Ba-Cu-O계 박막의 열처리 전 조성이 열처리 후 박막의 초전도특성 및 미세구조에 미치는 영향 (Effects of composition of preannealed Y-Ba-Cu-0 thin films deposited by sputtering on the superconducting properties and microstructure of post-annealed thin films)

  • 조해석;김형준
    • 한국재료학회지
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    • 제1권1호
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    • pp.54-61
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    • 1991
  • $YBa_2Cu_3O_{7-\delta}$ 단일 타게트를 사용하여 R. F. 마그네트론 스퍼터링법으로 MgO(100), Si(100)기판 위에 박막을 증착한 후, $880^{\circ}C$의 산소 분위기에서 1시간 동안 열처리를 하였다. 열처리 전 박막의 미세한 조성변화에 의해서도 열처리 후 박막의 미세구조 및 전기적 특성은 크게 변화했다. MgO(100)기판의 표면에 성장되는 입자들은 선택 배향적으로 성장하려는 경향을 가지므로 가늘고 길쭉한 입자 형상을 띠는 반면에 이들 입자위에 성장되는 다른 입자들은 결정 성장 방향의 선호도가 없으므로 둥근 모양의 입자형상을 가진다. 열처리 전 박학의 조성이 1-2-3을 벗어나면 증착 후 열처리할 때 액상이 형성되며, 액상의 양이 많을수록 선택 배향적 성장이 용이해져 texture를 쉽게 이룬다. 그러나 이러한 액상은 냉각 시에 초전도입자의 입계에 이차상으로 형성되기 때문에 초전도 박막의 전기적 특성, 특히 임계온도를 저하시킨다. 또한 $T_{c,\;zero}$$T_{c,\;on}$에 비해서 입계에 형성되는 이차상의 영향을 더 크게 받는다.

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자속커플링 SFCL의 사고전류 변화에 따른 전류제한특성 분석 (Characteristics according to increase of the fault current level of Flux-Coupling Type Superconducting Fault Current Limiter(SFCL))

  • 김용진;한병성;두호익;박충렬;두승규;김민주;하승룡
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.288-288
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    • 2008
  • The flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO thin films. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO thin film was connected with secondary coil in parallel. In a normal condition, the flux generated from a primary coil is cancelled out by its structure and the zero resistance of the YBCO thin films. When a fault occurs, the resistance of the YBCO thin films was generated and the fault current was limited by the SFCL. In this paper, we investigated the fault current limiting characteristics according to fault current level in the flux-coupling type SFCL. The experiment results that the fault current limiting characteristics was improved according to increase of the fault current level.

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MOD-TFA법에 의한 YBCO 박막의 제조 (Preparation of YBCO thin films by MOD-TFA process)

  • 김영국;유재무;고재웅;허순영;이동철
    • Progress in Superconductivity
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    • 제5권1호
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    • pp.80-83
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    • 2003
  • Superconducting YBCO thin films are fabricated on single-crystalline substrates by Metallo-organic Depostion process employing Trifluoroacetic acid as a chelating agent (MOD-TFA). (100)-oriented single crystalline LaAlO$_3$ substrates were employed to grow superconducting film with high crystallinity. The fully processed YBCO thin films were characterized with XRD, SEM, EDS, etc. The microstructures of YBCO thin films show labyrinth-like patterns. The origin of this microstructure was delineated by compositional inhomogeneity during the MOD process and it was shown that the microstructure may be modified by additives. In this work, effects of additives on the microstructures and electrical properties of YBCO thin films have been investigated.

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