Development of in situ Real Space Obserbation Method of Spin Transport

• Project/Area Number: 18K19014
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 29:Applied condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Hobara Rei 東京大学, 大学院理学系研究科(理学部), 特任研究員 (30568176)
• Co-Investigator(Kenkyū-buntansha): 白木 一郎 山梨大学, 大学院総合研究部, 准教授 (10399389)
• Project Period (FY): 2018-06-29 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000); Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2018: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
• Keywords: スピン / SPM / プローブ / グラフェン / スピン圧

Outline of Final Research Achievements

Our research is aiming to develop a special probe that can measure spin pressure "locally" and "electrically" with ease. We demonstrated that spin accumulation can be electrically detected at the interface between a ferro and a non-magnetic material. However, it became clear that quantitative measurement is difficult with conventional metal contacts. This difficulty came from the variations of the effective contact area of the probe apex, which cause spin diffusion amount change. We found that this issue could be improved by creating a protective layer on the probe. The protective layer needs to be durable, resistant to oxidation in the atmosphere, have a long spin diffusion length, and a high carrier density. We identified the feasibility of achieving these conditions with graphene or multilayer graphene.

Academic Significance and Societal Importance of the Research Achievements

スピンを使ったテクノロジーはスピントロニクスと呼ばれており、高速かつ低消費電力の電子デバイスへとつながる次世代の技術と期待されているが、その測定技術は通常の電子技術に比べて拙い。
スピン圧を検出するプローブ作成の端緒を得たことは、いまだほとんど手がついていないスピンの動的挙動やスピン輸送現象の解明に貢献し、新たなスピン物性やスピン材料科学への足掛かりとなり、スピントロニクスの発展に寄与すると考えている。