Investigation of length scale of spin-heat conversion phenomena

2019 Fiscal Year Final Research Report

• Project/Area Number: 19K21035
• Project/Area Number (Other): 18H05845 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Daimon Shunsuke 東京大学, 大学院工学系研究科(工学部), 助教 (20825434)
• Project Period (FY): 2018-08-24 – 2020-03-31
• Keywords: 熱流スピン流変換現象 / スピン流

Outline of Final Research Achievements

The spin Peltier and Seebeck effects refer to thermoelectric conversion effects using spin currents. These effects are still under the basic research stage, and our aim is to improve the thermoelectric conversion efficiency of these effects. To achieve this aim, we have investigated the principle of the thermoelectric conversion effects in terms of length scales. In this work, we measured thermoelectric effects with systematically changing thickness of spin current materials. Detailed analyses based on theoretical and numerical approaches reveal the length scales of the spin and heat current in the spin current materials. These results provide an important guideline for the improvement of the thermoelectric conversion efficiency.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的意義は、スピン流熱流変換現象を支配する長さスケールを解明することにある。従来のエレクトロニクスに用いられてきた電流とは対照的に、スピン流は非保存流であるという事実から、スピン流熱流変換現象には物質固有の長さスケールが現れる。この長さスケールを実験および理論の両面から解析し、スピン流と熱流がそれぞれ特有の拡散長が存在することを明らかにした。本成果により、長さスケールという観点からスピン流を最大限に利用するための方策が導かれ、熱電変換効率向上に向けた指針が示された。