超伝導

佐藤勝昭研究室の超伝導研究

■これまで行ってきた研究テーマ

　③　酸化物高温超伝導薄膜の結晶成長とデバイス応用
ペロブスカイト型酸化物磁性体・超伝導体のＭＢＥ成長とデバイスへの応用 （平成７，８年度科研費重点領域研究「モット転移」、平成８年度科研費奨励研究） Bi系高温超伝導体は、臨界温度(Tc)110 Kを持ち、大気中で安定であるという特徴を持つが、その結晶成長の難しさから良質の薄膜を得ることが困難であった。当研究室では、分子線エピタキシー(MBE)法により、原子・分子レベルでの結晶成長を行い、良質の薄膜の作製に成功した。さらに、その薄膜を用いて粒界型ジョセフソン接合の作製及び評価をおこなってきた。その結果、Bi系を用いたこの型の接合において初めて、交流ジョセフソン効果を確認している。現在、Bi系特有のイントリンジック（固有）ジョセフソン効果を用いたデバイスをめざす研究、および、磁性体から超伝導体へのスピン注入の研究を進めている。 最近、FIB加工したパターン基板を用いることによりＢｉ系超伝導薄膜（２２１２）において、ファセットが見られるような結晶性のよい微細構造を作製することに成功した。

■上記研究テーマの現在までの成果、データなど

高温超伝導体を用いた高性能デバイスの研究

■現在進めている研究テーマ

ペロブスカイト型酸化物磁性体・超伝導体のＭＢＥ成長とデバイスへの応用 （平成７，８年度科研費重点領域研究「モット転移」、平成８年度科研費奨励研究） 高温超伝導体の電磁波放出の非線形光学効果による研究　（平成11-12年度科研費奨励研究(A))

■上記テーマに関する論文・著書

2002 Academic Year

S. Kim, K. Lee, T. Ishibashi: Three Terminal Devices of Au / Cooper (II) Phthalocanine / Bi₂Sr₂CaCu₂O_8+delta Tunnel Junctions; Proc. The JST International Symposium on Superconducting Device Physics (SDP2001), Tokyo, June 25-28, 2001.
K. Lee, S. Kim , T. Ishibashi and I. Iguchi: Microwave Emission from Bi₂Sr₂CaCu₂O_y Intrinsic Josephson Junctions; Proc. The JST International Symposium on Superconducting Device Physics (SDP2001), Tokyo, June 25-28, 2001.
K. Lee, S. Kim, B. Friedman, T. Ishibashi, K.Sato and I.Iguchi: Microwave oscillation from BSCCO intrinsic Josephson junction arrays; Proc. Int. Superconductive Electronics Conf. 2001 (ISEC'01), Osaka, June 19-22, 2001.
K. Sato and T. Ishibashi: Magneto-optical and Reflectivity Studies in SrTiO₃; Proc. Magneto-Optical Recording International Symposium 2002, Benodet, France, May 6-9, 2002, Trans. Magn. Soc. Jpn. 2 [4] (2002) 167-170.
T. Ishibashi, K. Yonemitsu, K. Inagaki and K. Sato: Crystal Growth of BiSrCaCuO Thin Films on Submicron-size Step Structures; J. Cryst. Growth 237-239(2002), Part 1, 762-766.
S. Kim, Jungyoon E, K. Lee, T. Ishibashi, K. Sato and B. Friedman: Polaronic quasiparticle injection in organic copper (II) phthalocyanine/Bi2Sr2CaCu2O8+delta tunnel junctions; Appl. Phys. Lett. 80 [14] (2002) 2526-2528.

2001 Academic Year

T. Ishibashi, Kz. Sato, K. Yonemitsu, K. Sato, K. Lee and S. Kim: Spin injection properties and conductance spectra of Co/Au/YBaCuO and Co/Au/BiSrCaCuO tunnel junctions; Proc. Int. Superconductive Electronics Conf. 2001 (ISEC'01), Osaka, June 19-22, 2001, Supercond. Sci. Technol. 14 (2001) 1014-1017.

K.Yonemitsu, K.Inagaki, T.Ishibashi, K.Sato, S.Kim and K.Lee: Electrical Properties of Bi₂Sr₂CaCu₂O_x Submicron Structures Grown on Patterned Substrates; Proc. The JST International Symposium on Superconducting Device Physics (SDP2001), Tokyo, June 25-28, 2001, Physica C 367 (2002) 414-418.

T. Ishibashi, Kz. Sato, K. Yonemitsu and K. Sato: Spin tunneling in Co/Au/BiSrCaCuO tunnel junction; Proc. Joint MMM-Intermag Conference, San Antonio, Texas, Jan. 7-11, 2001, J. Appl. Phys. 88 (2001) 7672-7674.

2000年

T. Ishibashi, Kz. Sato and K. Sato: Anomalous Zero-bias Behavior in Co/BiSrCaCuO and Au/BiSrCaCuO Tunnel Junctions; Proc. 6th Int. Conf. Materials and Mechanisms of Superconductivity and High Temperature Superconductors, Houston, Texas, February 20-25, 2000, Physica C 341-348 (2000) 1615-1616.
T. Ishibashi, Kz. Sato, G. Gu, N. Koshizuka and K. Sato: Tunneling Spectra of Co/I/BiSrCaCuO Tunnel Junctions; Jpn. J. Appl. Phys. 39 Part 2 [4A] (2000), 281-283.
I. Iguchi, K.J. Lee, E. Kume, T. Ishibashi and K. Sato: Nonequilibrium microwave emission due to tunnel injection of quasiparticles into a high-Tc Bi₂Sr₂CaCu₂O_y superconductor; Phys. Rev. B61 [1] (2000) 689-693
1999年
T. Ishibashi, T. Kawahara, H. Kaneko and K. Sato>: Submicron-size Fabrication of BSCCO Thin Films by using Patterned Substrates; Proc. Applied Supercunductivity Conference 1998, Palmsprings, IEEE Trans. Appl. Superconductivity 9 [2] (1999) 2383-2386.
T. Kawahara, T. Ishibashi, H. Kaneko, K. Sato, K. Lee and I. Iguchi: Off-axis BSCCO Intrinsic Josephson Junction: Proc. Applied Supercunductivity Conference 1998, Palmsprings, IEEE Trans. Appl. Superconductivity 9 [2] (1999) 4519-4522
K.J. Lee, Wan Wang, I. Iguchi, B. Friedman, T. Ishibashi, and K. Sato: Spin-polarized quasiparticle tunnel injection in a YBa₂Cu₃O_y/Au/Co junction; Appl. Phys. Lett. 75 [8] (1999) 1149-1151.
1998年
T. Ishibashi, K. Sato, K.J. Lee and I. Iguchi: Microwave Properties of Intrinsic Bi2Sr2CaCu2Oy Josephson Junctions on Off-axis Substrate, Proc. 3rd European Conference on Applied Superconductivity, EUCAS'97, Netherlands, June 30-July 3, 1997 Inst. Phys. Conf. Ser. No 158 (IOP Publishing, London, 1998) 527-530.
T. Ishibashi, T. Kawahara, H. Kaneko and K. Sato: Submicron-size Fabrication of Bi2Sr2CaCu2Ox Thin Films by Utilizing Facet Growth; Jpn. J. Appl. Phys. 37 Part 2, [7B] (1998) L863-865.
1997年
T. Ishibashi, T. Kawahara, K. Sato, K.J. Lee, I. Iguchi and M. Kawabe: Anisotropic Transport Properties in Twin-Free Bi2Sr2CaCu2Ox Thin Films; Jpn. J. Appl. Phys. 36 Part 1 [12A] (1997) 7175-7176.
K. Lee, I. Iguchi, T. Ishibashi, K. Sato, H. Soutome and M. Kawabe: Josephson Junction Properties of Bi2Sr2CaCu2Oy Bicrystal Junctions Grown by Sequential Deposition Technique Using Molecular Beam Epitaxy; Proc. 1996 Appl. Supercond. Conf., August 25-30, 1996, IEEE Trans. Appl. Superconductivity 7, [2] (1997) 2300-2303.
1996年（一部、石橋助手の筑波大での研究成果）
K. Lee, I. Iguchi, T. Ishibashi and K. Sato: Internal Anisotropic Microwave Frequency Noise in HTSC BSCCO and YBCO Junctions; Advances in Superconductivity IX, Proc. 9th Int. Symp. Superconductivity (ISS'96), Sapporo, October 21-24, (Springer, Tokyo, 1997) 1253-1256.
T. Ishibashi, K. Sato, K.J. Lee, I. Iguchi and M. Kawabe: Crystallographic and Anisotropic Transport Properties in Untwinned Bi2Sr2CaCu2Oy Thin Films; Advances in Superconductivity IX, Proc. 9th Int. Symp. Superconductivity (ISS'96), Sapporo, October 21-24, (Springer, Tokyo, 1997) 1089-1092.
K. Lee, I. Iguchi, T. Ishibashi and M. Kawabe: Josephson transport and crystallographic properties of Bi2Sr2CaCu2Oy junctions on (100) MgO bicrystal substrates; Physica C 257 (1996) 99-104.
Y. Kumagai, K. Ishimoto, R. Mori, K.-M. Tee, T. Ishibashi, M. Kawabe and F. Hasegawa: 4-Monolayer-Height Layer-by-Layer Growth and Increase of the Critical Thicness of Ge Heteroepotaxy on Boron-Peradsorbed Si(111) Surface; Jpn. J. Appl. Phys. 35, [4B] (1996) L476-L478.
1995年以前(石橋助手の筑波大での研究成果)
T. Ishibashi, H.i Soutome, Y. Okada and M. Kawabe: Bi2Sr2Can-1CunOx Thin Films by Growth Interruption Technique; J. Crystal Growth 150 (1995) 1094-1097.
T. Ishibashi, H. Soutome, Y. Okada and M. Kawabe: Surface Diffusion in Molecular Beam Epitaxy of Bi2Sr2Can-1CunOx IEEE Trans. Aappl. Supercond. 5 [2] (1955) 1805-1809.
T. Ishibashii, Y. Okada and M.o Kawabe: Surface diffusions for Bi2Sr2CuOx+6 Thin Films Grown by Molecular Beam Epitaxy; Jpn. J. Appl. Phys. 33 [6A] (1994) L763-L765.
T. Ishibashi, T. Fujita, K.-H. Song, Y. Okada and M. Kawabe: Bi2Sr2CuOx Thin Films with (011) Vicinal Surfaces Fabricated on Vicinal LaSrGaO4 (110) by Molecular Beam Epitaxy; Jpn. J. Appl. Phys. 32 [2B] (1993) L257-L259.
T. Ishibashi, K.-H. Song, Y. Okada and M. Kawabe: Two-Dimensional Epitaxial Growth of Bi2Sr2CuOx on Tilted SrTiO3(001) Substrates Studied by Reflection High Energy Electron Diffraction; Jpn. J. Appl. Phys. 31 [4A] (1992) L406-L409.
S. Yokoyama, T. Ishibashi, M. Yamagami and M. Kawabe: Atomic Layer Growth of Bi-Sr-Ca-Cu-O by Molecular Beam Epitaxy Using Ozone under UV Irradiation; Jpn. J. Appl. Phys. 30 [1B] (1991) L106-L109.
T. Ishibashi, Y. Okada, S. Yokoyama and M. Kawabe: Layer by Layer Growth of Bi-Sr-Ca-Cu-O Superconducting Films by Molecular Beam Epitaxy; Jpn. J. Appl. Phys. 30 [12B] (1991) 3900-3903.

佐藤研究室紹介のページへ