Creation of solid phase change materials by controlling electronic/spin phase transitions

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22073
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Fujita Asaya 国立研究開発法人産業技術総合研究所, 材料・化学領域, 研究チーム長 (10323073)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 相変化畜熱 / 電子相 / 電子相関 / 焼結

Outline of Final Research Achievements

Since conventional Phase Change Materials (PCMs) utilize a liquid-solid phase change as a source of latent heat, a capsule/tank is necessary to equip them into the machine or electronic devices, preventing a smooth heat exchange. In this study, all solid PCM is developed by utilizing the "electronic phase" and its transition. By accounting the freedom of the order parameter, the amount of latent heat becomes matches the magnitude of the electron-correlation at the grand state. In the VO2 oxide, which exhibits a poor sinterability due to the unique electronic state, high strength and high heat density were both realized by improving the sintering method. As a result, the regenerative actions were confirmed by using simple ceramic bulk block which has directly curved grooves as a micro channel.

Free Research Field

電子・磁気機能材料

Academic Significance and Societal Importance of the Research Achievements

相変化型畜熱材料(PCM) は、熱密度が大きく、排熱・未利用熱利用などの面での活用が期待されている。従来の相変化型畜熱材料で問題となる融液経由を回避するために、固体畜熱材料の開発を行った。いわゆる強相関系において、秩序変数の自由度が大きいと、電子相関を反映して大きな潜熱が得られることを示した。また、新たな材料候補の提案を行った。さらに温度帯や履歴問題などを解決するための方策をさぐり、広い温度帯で活用できる材料の設計指針を明らかにした。また、熱物性の利点を生かしたまま高強度バルク形成を実現することで、材料としての応用展開に目処をたてた。