Faculty Profiles - KIM Seokbeom

TYTBa2CU3O7-delta thick films grown on textured metal substrates by liquid-phase epitaxy process

T Maeda, SB Kim, T Suga, H Kurosaki, T Yuasa, Y Yamada, Y Yamada, H Yoshino, M Yamazaki, TD Thanh, T Watanabe, K Matsumoto, Hirabayashi, I

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 11 ( 1 ) 2931 - 2934 2001.3

Language：English Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Towards high-current wire application of high-temperature superconductors, YBa2Cu3O7-delta (YBCO) thick films are grown by means of a Liquid-phase epitaxy (LPE) process on a (001) surface of NiO single crystal and Laser-sputtered NiO buffer layer deposited on a (001) surface of SrTiO3 single crystal. NiO buffer layers can be rapidly formed on textured Ni tape by the recently developed "Surface-Oxidation-Epitaxy" (SOE) technique which is expected to be a low-cost production method of long metal substrates with highly-textured oxide buffer layer. LPE growth on SOE-buffered textured Ni tapes are also attempted. Moreover, we successfully prepared similar to0.1 m-long LPE-YBCO tapes on {120}< 2(1) over bar 0 > Ag-0.1 wt.% Cu alloy tape by using a specially designed LPE furnace equipped with a "reel-to-reel" attachment. BaF2-added BaO-CuO flux is used in this work, in which the growth temperature of YBCO is drastically lowered from usually used value of similar to 1000 degreesC down to 900-930 degreesC, While current transport performances of these LPE-YBCO films are still insufficient for high-current wire application, the present results show the high potential of this LPE process for long-length coated-conductor production.

DOI： 10.1109/77.919676

Fabrication of NdGaO3 buffer layer on textured Ni tape for long length coated conductors

SB Kim, T Maeda, Y Yamada, T Suga, K Matsumoto, T Watanabe, Hirabayashi, I

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 11 ( 1 ) 3317 - 3320 2001.3

Language：English Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Biaxially aligned NdGaO3 (NGO) layers were successfully fabricated on the single crystalline substrates (STO, LAO and NiO/STO) and metalic substrate (NiO/Ni) by pulsed laser deposition (PLD) method and post-annealing process. And also, the good biaxial orientation YBa2Cu3O7.delta (YBCO) films on NGO layers were deposited by liquid phase epitaxy (LPE) method. From this work, it has been proved for the first time that NGO thin film can be used as a seed layer for the YBCO thick film deposition by LPE method. And it is clear that the NGO thin film growth process, where biaxially orientated films were deposited using PLD at room temperature followed by simple post-annealing process, is very effective for the uniform long length coated conductor production.

DOI： 10.1109/77.919772

Long-length Y-Ba-Cu-O coated conductors produced by surface-oxidation epitaxy method

K Matsumoto, T Watanabe, T Tanigawa, T Maeda, S Kim, Hirabayashi, I

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 11 ( 1 ) 3138 - 3141 2001.3

Language：English Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

A 50-m long, biaxially textured NiO buffer layer for epitaxial growth of YBa2Cu3O7-delta (YBCO) film has been fabricated on a long length cube-textured Ni tape using surface-oxidation epitaxy (SOE) technique. The thickness of NiO layer was arranged to be around 3 mum. The tape manufacturing speed was 15 m/h, The SOE-NiO layer was highly (100) oriented and the full width at half maximum from X-ray phi -scan for NiO(111) was varied from 13 to 19 degrees in the whole length. J(c) values exceeding 0.3 MA/cm(2) at 77K and self field have been obtained in short samples of YBCO films on NiO/Ni tapes, by using thin MgO cap layer with the thickness of about 100 nm, Crystal orientation control of YBCO coated conductors by SOE method is very effective even for the long length Ni tapes.

DOI： 10.1109/77.919728

Fabrication of buffer layer for YBCO coated conductor on cube textured Ag substrate

T. Yuasa, H. Kurosaki, S. B. Kim, T. Maeda, K. Higashiyama, I. Hirabayashi

Physica C: Superconductivity and its Applications 357-360 934 - 937 2001

Language：English

In case of the cube textured (CUTE) Ag substrate, recrystallization process of as-rolled Ag substrate in various atmosphere changed surface flatness of the substrate. When the substrate was heated in a vacuum chamber with a oxygen partial pressure of less than 1 × 10-5 Torr at 600°C, the surface average roughness (Ra) of the substrate was less than 120 nm. Then the oxygen was introduced into the vacuum chamber to fabricate CeO2 buffer layer on the substrate by pulsed laser deposition. After the oxygen pressure reached to 50-150 mTorr, CeO2 layer was deposited on the CUTE Ag substrate immediately. By reducing the influence of oxygen to surface roughness of the substrate, Ra of the CeO2 buffered CUTE Ag substrate was 30 nm. © 2001 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(01)00446-4

Characterization of YBa2Cu3O7-δ films grown on NiO buffer layer by liquid-phase epitaxy process

Tomonori Watanabe, Kaname Matsumoto

Physica C: Superconductivity and its Applications 357-360 1042 - 1045 2001

Language：English

By means of a liquid-phase epitaxy (LPE) process, superconducting YBa2Cu3O7-δ (YBCO) thick film is grown on a biaxially textured NiO buffer layer which is pulsed-laser deposited on a (0 0 1) surface of SrTiO3 single crystal. Employment of BaF2-added Ba-Cu-O flux is found to be effective for LPE-YBCO growth because the growth temperature of YBCO is drastically lowered down to 900-920°C compared to the case of usually used simple Ba-Cu-O flux. This strongly suggests that the low-temperature LPE growth of YBCO on a NiO/Ni substrate is hopeful process for coated-conductor production. Superconductivity transition temperature (Tc) of the LPE-YBCO film is measured to be 91 K for onset and 87 K for a zero-resistance state. © 2001 Elsevier Science B.V.

DOI： 10.1016/S0921-4534(01)00528-7

Fabrication of seed/buffer layers on metallic substrates for YBCO coated conductors

SeokBeom Kim, Toshihiko Maeda, Yasuji Yamada, Toshihiro Suga, Yutaka Yamada, Tomonori Watanabe, Kaname Matsumoto, Isumi Hirabayashi

Physica C: Superconductivity and its Applications 357-360 979 - 982 2001

Language：English

LaNiO3 (LNO) buffer layers with good c-axis orientation on SrTiO3 (STO), LaAlO3 (LAO), NiO/STO and SOE (NiO/Ni) tapes were successfully fabricated by the pulsed laser deposition (PLD) method. Biaxially aligned neodymium (NdGaO3, NGO) seed layers were successfully fabricated on the STO, LAO and LNO buffer layer by PLD method and post-annealing process. And also, the good biaxial orientation YBa2Cu3O7-δ (YBCO) films on NGO seed layers were deposited by liquid phase epitaxy (LPE) method. From this work, it has been proved for the first time that NGO thin film can be used as a seed layer for YBCO thick film deposition by the LPE method. This NGO thin film which is deposited by the PLD method at room temperature and post-annealed at 950°C for 5 h in air, is low cost and very effective for the coated conductor production by LPE. © 2001 Elsevier Science B.V.

DOI： 10.1016/S0921-4534(01)00464-6

A study on stability criterion for cryocooler operating HTS coils

A. Ishiyama, S.B. Kim, K.H. Han

大韓電気学会論文誌（韓国） 2001

Non-cuprate thin films as candidates of seed layer for liquid phase epitaxy process

Tadamasa Miura, Yasuji Yamada, Toshihiro Suga, Daxiang Huang, Seok Beom Kim, Toshihiko Maeda, Izumi Hirabayashi, Hiroshi Ikuta, Uichiro Mizutani

Physica C: Superconductivity and its Applications 357-360 983 - 986 2001

Language：English

As a seed layer for the liquid phase epitaxy (LPE) of YBa2Cu3O7-d (YBCO) we investigate non-cuprate thin film of Y-Ba-Fe-O deposited by pulsed laser deposition (PLD) method. The deposited film is highly oriented and it can be used as a seed layer at LPE temperatures below 980°C. PLD conditions for obtaining crystalline Y-Ba-Fe-O film is much wider than that for the seed layer of YBCO. LPE-grown YBCO film formed on the Y-Ba-Fe-O seed layer shows the same superconductive properties as that formed on the YBCO seed layer. © 2001 Elsevier Science B.V.

DOI： 10.1016/S0921-4534(01)00465-8

Preparation of YBCO films on CeO2 buffered metallic substrates by the TFA-MOD method

Y. Takahashi, T. Araki, K. Yamagiwa, Yutaka Yamada, S. B. Kim, Y. Iijima, K. Takeda, I. Hirabayashi

Physica C: Superconductivity and its Applications 357-360 1003 - 1006 2001

Language：English

Biaxially aligned YBa2Cu3O7-y (YBCO) coated conductors on long metallic substrates are required for power applications. Recently trifluoroacetate-metal organic deposition (TFA-MOD) has been well-known as the most prospective method for the preparation of high Jc YBCO films and it has been applied on metallic substrates. We optimized the deposition condition of the CeO2 films on IBAD tapes and fabricated 10 cm class in-plane textured CeO2 buffered IBAD tapes by the PLD method. We prepared YBCO films on CeO2 buffered IBAD tapes by the TFA-MOD method. The YBCO films deposited on the buffered tapes were out of plane and in-plane aligned. The Jc value for short sample was 1.72 MA/cm2 at 77 K, 0 T. These results suggest that the CeO2 buffered IBAD tapes are feasible for the substrate for YBCO coated superconducting wire by the TFA-MOD method. © 2001 Elsevier Science B.V.

DOI： 10.1016/S0921-4534(01)00470-1

Fabrication of buffer layers and seed layers on biaxially textured Ni tapes for YBCO superconducting wire

H. Kurosaki, T. Yuasa, T. Maeda, Y. Yamada, S. B. Kim, T. Watanabe, K. Wada, I. Hirabayashi

Physica C: Superconductivity and its Applications 357-360 938 - 941 2001

Language：English

We have deposited Y2O3 buffer layers by metal-organic chemical vapor deposition (MOCVD) on textured Ni tapes coated with biaxially aligned NiO(1 0 0) layers grown by surface oxidation epitaxy method. X-ray diffraction measurements showed that Y2O3 grew cube-on-cube on NiO layer, i.e. it has also biaxial orientation. With these Y2O3 layers, in-plane aligned YBa2Cu3O7-δ (YBCO) (0 0 1) thick films (∼3 μm in thickness) have been successfully grown by liquid phase epitaxy (LPE) method on the textured Ni tapes. YBCO seed layers, required in LPE process, had been also deposited by MOCVD. The LPE-grown YBCO thick films exhibit superconductivity transition temperature of Tc, onset = 90 K and Tc, zero = 65 K by four-probe transport measurement. © 2001 Elsevier Science B.V.

DOI： 10.1016/S0921-4534(01)00447-6