• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.365-367
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• 2002

A serious problem in using YBCO films for fault current limiter is inhomogeneities caused by imperpect manufacturing. So simultaneous quenches are a difficult problem which elements for current limiting are connected in series for increasing voltage ratings. We investigated extended electric field - current characteristics for current limiting element of YBCO film when 0-130mT magnetic field is applied. And quench characteristics were investigated in over all element and between elements of YBCO films. From the experiments, it was shown that applied magnetic fields using solenoid coil induced uniform quench distribution for over all stripes and simultaneous quench in all elements for current limiting of YBCO film was realized.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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• pp.49-52
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• 2003

BiSrCaCuO superconducting thin films have been fabricated by co-deposition using IBS(Ion Beam Sputtering) method. Despite setting the composition of thin film Bi2212 or Bi2223, in both cased, Bi2201, Bi2212 and Bi2223 phase were appeared. It was confirmed the obtained field of stabilizing phase was represented in the diagonal direction of the right below end in the Arrhenius plot of temperature of the substrate and $PO_3$ and it was distributed in the reeone.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.115-118
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• 1991

The temperature distribution on the superconducting thin-film is analyzed as moving constant field is applied above upper critical field. The distribution of magnetic field is derived in the normal spot. Governing equation is obtained with the help of the equation of conservation of energy. The temperature distribution and the heat dissipation are obtained through computer simulation by the method of numerical analysis. Maximum temperature is occured in the most right side inside normal spot. The temperature is increased abruptly inside the normal spot, and decreased more gradually outside normal spot in the direction of moving field as velocity is increased. Increasing the velocity rather than increasing magnitude of the normal spot and the applied field makes maximum temperature larger. Heat dissipation is affected by the velocity rather than the magnitude of normal spot and the applied field.

• 수산해양기술연구
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• 제30권4호
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• pp.350-356
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• 1994

We have prepared superconducting Bi-Pb-Sr-Ca.Cu-O thin films by RF magnetron sputtering technique, on heated MgO(100) substrates. Sputtering was carried out in a mixture of argon and oxygen(10%) and the pressure was maintained at 5 mTorr during deposition. The substrate temperature was maintained $400^{\circ}C$ during deposition. The films sputtered were amorphous and insulating. All the films became superconducting by annealing, The films annealed at $880^{\circ}C$ for 30 minutes in air showed high-Tc phase with zero resistivity of 93K. These results indicate that the growth of the high-Tc phase is promoted by the presence of Pb at annealing temperature.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.518-521
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• 2003

Bi$_2$Sr$_2$Ca$_{n-1}$Cu$_{n}$O$_{x}$ superconducting thin films have been fabricated by atomic layer-by-layer deposition using IBS(Ion Beam Sputtering) method. During the deposition, 90 mol% ozone gas of typical pressure of 1~9 $\times$ 10$^{-5}$ Torr are supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then Bi-2201 oriented along the c-axis is grown.grown.

• 전기의세계
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• 제24권6호
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• pp.67-71
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• 1975

어떤 자성재료에 대해서는 자기특성 이외에 유리부착성, 탄성, 접점에서의 특성 등이 요구되며 이러한 요구들을 한가지 재료로서 만족시키는 것은 곤란하므로 재료의 복합화가 시도되고 있다. Wire memory는 동선상에 permalley를 전착시킨 것이고 이것을 Core에 digit선이 통한 것으로 볼 수 있다. 금후로는 자성재료부품에서도 전자부품에서와 마찬가지로 재료를 복합소형화하여 일괄생산하는 방향으로 나아갈 것이 예상된다. 한편으로는 기억의 고밀도화가 강하게 요구되고 있으며 이에 따라 자성박막의 자벽 그 자체를 기억체로 이용하려는 방향으로 나아가고 있다. 이 경우, 기억체를 자기유도에 의하여 읽어내는 것은 S/N비가 적어서 곤란하고 Faraday효과, Kerr효과 등을 이용한 자기광학적 방법이 유효하다. 요즘 많이 연구되고 있는 초전도현상에 있어서고 재료의 자성이 도전율에 절대적인 영향을 미치므로 이에 관해서는 자성재료연구분야에서도 많은 관심이 모아지고 있다. 따라서 초전도재료에 관하여서도 따로 소개하고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.613-616
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• 2001

Bi$_2$Sr$_2$CuO$_{x}$ thin films have been fabricated by atomic layer-by-layer deposition using ion beam sputtering(IBS) method. During the deposition, 10 and 90 wt%-ozone/oxygen mixture gas of typical pressure of 1~9$\times$10$^{-5}$ Torr are supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then Bi-2201 oriented along the c-axis is grown.n.

• 한국전기전자재료학회논문지
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• 제19권4호
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• pp.391-397
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• 2006

We present investigations of a hybrid type superconducting fault current limiter (SFCL), which consists of transformers and resistive superconducting elements. The secondary windings of the transformer were separated into several electrically isolated circuits and linked inductively with each other by mutual flux, each of which has a superconducting current limiting element of $YBa_2Cu_3O_7$ (YBCO) stripes as a current limiting element. Simple connection in series of the SFCL elements tends to produce ill-timed quenching because of power dissipation unbalance between SFCL elements. Both electrical isolation and mutual flux linkage of the elements provides a solution to power dissipation unbalance, inducing simultaneous quench and current redistribution of the YBCO films. This design enables to increase the voltage rating of SFCL with given YBCO stripes.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.67-70
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• 1999

We have fabricated YBa$_2Cu_3O_{7-x}$ thin films by cylindrical hollow cathode sputtering. For 2 inch diameter of MgO (100) substrate, we obtained the zero resistance temperature in the range from 83 K to 86 K and thickness uniformity better than 5 % over the whole area. Also, the average deposition rate was 100nm/h which is higher than 10 times compare to conventional off-axis sputtering method. These results indicate that cylindrical hollow cathode sputtering seems to have unique capabilities for high rate and homogeneous deposition of large area thin film.

• 한국진공학회지
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• 제4권2호
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• pp.172-176
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• 1995

$YBa_2Cu_3O_{7-y}$ thin films have been prepared on MgO(100)substrates placed on-axis to the target by dc magnetron sputtering in a variety of oxygen/argon gas pressures with different substrate-target distances. We found that films with the c-axis perpendicular to the substrate deposited in an optimally high gas pressure with on-axis substrate-target configuration do. Increasing the substrate-target distance was found to be effetive in reducing the resputtering effect and enhancing superconductivity of films, but not so much $\alpha$-and c-axis growth of YMCO films on MgO substrates. Dependences of the Tc, the rationj of resistances at 300K and 100K, and the X-ray diffraction pattern on the gas pressure and the substrate target distance are described.