Realization of superconducting phase elements with arbitrary values using magnetic Josephson junctions and their applications to superconducting circuits

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04291
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Daido University
• Principal Investigator: Akaike Hiroyuki 大同大学, 工学部, 教授 (20273287)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 超伝導デバイス / 超伝導集積回路 / 磁性ジョセフソン接合 / デバイス作製技術 / 窒化物超伝導体

Outline of Final Research Achievements

In this study, we investigated characteristics of the superconducting phase shift elements with arbitrary values based on magnetic Josephson pi-junctions to develop superconducting phase shift technologies which are useful for superconducting digital circuits. Furthermore, we studied the effects of an introduction of the elements on the operation and performance of the circuits, and found that control of the polarity of the phase shift of them is crucial. We also developed a novel Josephson tunnel junction with a superconducting NbTiN material which has a long magnetic penetration depth effective in miniaturization of the elements.

Free Research Field

超伝導エレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

超伝導位相シフト技術は、超低消費電力性を特長とする超伝導集積回路や量子コンピュータに使われる超伝導量子回路において、非常に重要な技術となりうる。本研究で検討した素子は、従来のジョセフソンπ-接合単体では位相シフト量がπとなるのに対して、π/2程度のものからπ程度のものまで種々の位相シフト量を実現できる。本成果は、この素子の実現可能性や回路への適用可能性を示すものであり、超伝導位相シフト技術の発展につながることから、その学術的意義は大きい。