Flat and Lateral High-Tc Superconducting Junctions Applied to Millimeter-Wave Mixer

Katsumi SUZUKI  Seiichi TOKUNAGA  Masahito BAN  Masashi OHTSUKA  Youichi ENOMOTO  

IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.9   pp.1233-1236
Publication Date: 1996/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Issue on Toward Digital and Analog Applications of Superconductors)
Category: Analog applications
superconductor,  junction,  millimeter-wave,  mixer,  

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Here we report on a fabrication and a millimeter-wave performance of reliable and reproducible high-Tc superconducting (HTS) Josephson junctions on MgO substrates using a focused Ga ion beam (FIB). The junction normal resistance Rn can be controlled by making the junction in a series. The Rn depends on space between each junction in the series structure. A mechanism of the junction is proposed by measuring cross-sectional transmission electron microscopy (TEM) images and their X-ray spectra of Ga, Y, Ba, Cu, Mg and O. The junctions with more than 1 µm spaces, and flat and lateral structure are independent each other for the crystallization process. We observe the HTS mixer-antenna performance as fundamental/harmonic mixers in the wide frequency range up to 100 GHz.