Presentation 2008-01-25
Josephson junctions using as-grown MgB_2 thin films
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Abstract(in English) We describe the fabrications of as-grown MgB_2 thin films and Josephson junctions. MgB_2 thin films were deposited by the co-evaporation and sputtering methods, and we obtained the critical temperature of 37K by co-evaporation method, and 29K by sputtering method. We investigated the dependence of the critical temperature and resistivity on the film thickness, and obtained the critical temperature of 8K when the film thickness was 4.5nm. As the SIS junctions, we fabricated multi-layered MgB_2/AlN/MgB_2 junctions, which showed the clear Josephson current and gap structures. The current density was obtained of 114A/cm^2 and the 2Δ of 3.7mV. As the overdamped junctions, we fabricated the MgB_2/Al/AlN/MgB_2 multilayered junctions, and obtained the current-voltage characteristics, which fit an ideal RSJ model, and its I_CR_N products were obtained of 190μV. The critical current was ideally modulated by applying an external magnetic field, which showed that the Josephson current flowed uniformly in the junctions. By an irradiation of 95.622GHz millimeterwave, clear Shapiro steps were observed, and its step heights were well fitted by theoretical calculation of RSJ model. We fabricated the 11-series MgB_2/Al/AlN/MgB_2 junctions, in which current-voltage characteristics indicated that the uniformity of the characteristics between junction and junction was quite well.
Keyword(in Japanese) (See Japanese page)
Keyword(in English) MgB_2 / Co-evaporation / Sputtering / Josephson junction / SIS junction / Overdamp junction / RSJ model
Paper # SCE2007-26
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Conference Information
Committee SCE
Conference Date 2008/1/18(1days)
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Paper Information
Registration To Superconductive Electronics (SCE)
Language JPN
Title (in Japanese) (See Japanese page)
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Title (in English) Josephson junctions using as-grown MgB_2 thin films
Sub Title (in English)
Keyword(1) MgB_2
Keyword(2) Co-evaporation
Keyword(3) Sputtering
Keyword(4) Josephson junction
Keyword(5) SIS junction
Keyword(6) Overdamp junction
Keyword(7) RSJ model
1st Author's Name Hisashi SHIMAKAGE
1st Author's Affiliation National Institute of Information and Communications Technology()
2nd Author's Name Zhen WANG
2nd Author's Affiliation National Institute of Information and Communications Technology
Date 2008-01-25
Paper # SCE2007-26
Volume (vol) vol.107
Number (no) 458
Page pp.pp.-
#Pages 6
Date of Issue