Innovation in Molecular Ferroelectrics: Development of High-Performance Pyroelectric and Piezoelectric Materials Based on Plastic Crystals

2023 Fiscal Year Final Research Report

• Project/Area Number: 19H00884
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
• Research Institution: Hokkaido University
• Principal Investigator: Harada Jun 北海道大学, 理学研究院, 准教授 (00313172)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 分子性固体

Outline of Final Research Achievements

We have already developed a new type of molecular ferroelectrics and named them as plastic/ferroelectric crystals. This type of crystals can show ferroelectric performance even in bulk polycrystals because the plastic crystal phase of the crystals in the high temperatures has a cubic crystal structure. In this study, we have further proceeded in the development of these plastic/ferroelectric crystals and developed many new ferroelectric crystals. We have succeeded in developing crystals that show ferroelectric polarization switching under low electric fields, crystals with extremely high pyroelectricity and piezoelectricity, and crystals that can be fabricated into a variety of shapes by melt processes.

Free Research Field

機能物性化学

Academic Significance and Societal Importance of the Research Achievements

現在広く用いられている高性能なセラミクス強誘電体の多くは有毒な鉛を含むため，その代替材料の開発が強く求められている．本研究で開発した柔粘性/強誘電性結晶は，粉末を固めた多結晶体で強誘電性を示すという，従来の分子性強誘電結晶では不可能な特性を実現している．そして，非常に低い電場で分極反転可能な結晶の開発に成功し，多結晶体での様々な活用が可能となっている．また，融解加工により様々な形状に加工できる結晶の開発にも成功している．