Open AccessA Study of the HTS Josephson Junction Formed by a Ga Focused Ion Beam
Author(s) -
K. Hayashi,
Teppei Ueda,
Ryo Ohtani,
Seiichiro Ariyoshi,
Saburo Tanaka
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1590/1/012044
Subject(s) - materials science , focused ion beam , josephson effect , squid , fluence , irradiation , ion beam , superconductivity , optoelectronics , ion , substrate (aquarium) , microwave , acceleration voltage , condensed matter physics , electron , cathode ray , chemistry , physics , ecology , oceanography , organic chemistry , quantum mechanics , geology , nuclear physics , biology
High Temperature Superconductor Josephson Junctions (HTS-JJs) are based on artificial grain boundaries. However, the layout of HTS Superconducting QUantum Interference Devices (SQUIDs) on a bi-crystal substrate was restricted. Therefore, we considered to form low noise nano-bridge JJs by Ga Focused Ion Beam (Ga-FIB) irradiation. An 100 nm thick and 4 μm wide YBa 2 Cu 3 O 7- δ (YBCO) micro-channels protected by a 20 nm thick Au protection layer were irradiated by line scans of Ga-FIB (Acceleration voltage: 40 kV, Beam diameter: ∼30 nm) and they were became normal conductivity except for the restricted region. In those nano-bridges, W N = 500 nm and fluence Φ = 2.0×10 15 ions/cm 2 of the nano-bridge was I C = 170 μA and we confirmed Shapiro steps by microwave irradiation of f RF = 2 GHz.