Development of spin injection technology through energy-band symmetry matching in semiconductor-based spin devices

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18719
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: Osaka University
• Principal Investigator: Yamada Michihiro 大阪大学, 大学院基礎工学研究科, 特任准教授(常勤) (50778529)
• Co-Investigator(Kenkyū-buntansha): 本多 周太 関西大学, システム理工学部, 准教授 (00402553)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: ゲルマニウム / スピン注入 / ホイスラー合金

Outline of Final Research Achievements

The spin injection into semiconductor is core technology for development of semiconductor-based devices. In this study, we tried to develop the highly efficient and low resistive spin injection technique using novel ferromagnet/metal atomic layers/semiconductor structures without insulating tunnel barrier.
At first, we explored the effect of inserted metal species on spin transport properties. From the results, it was found that the interfacial magnetism depending on the metal species dominates magnetoresistance (MR) ratio and temperature dependence of the MR ratio. We also demonstrated the improvement of thermal stability of spin injection contact by utilizing appropriate Co-based Heusler alloys.
From the above, we revealed the important factor in spin injection interface and developed the novel contact structure with highly efficient and low resistive junctions for device applications.

Free Research Field

半導体工学

Academic Significance and Societal Importance of the Research Achievements

本研究では，原子層レベルで制御したエピタキシャル強磁性体/半導体界面を用いることで，数原子程度の界面磁性がスピン注入効率に対して影響を与えており，さらにその温度依存性がブロッホ則で説明されることを明らかにした．これは，これまで実験的に観測が不可能であった強磁性体/半導体界面でのスピン注入機構に関する学理構築に資する成果である．さらに，これらの温度依存性や注入効率に関する知見は，室温でのスピン注入増大という工学的な意義もあり，今後の室温スピンデバイスの高性能化に向けた指針を示す．