New method for characterization of plastic crystals using terahertz spectroscopy

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K05443
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: Akita University
• Principal Investigator: Tanno Takenori 秋田大学, 地方創生センター, 准教授 (70390721)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 柔粘性結晶 / 相転移 / テラヘルツ分光

Outline of Final Research Achievements

A group of substances called "plastic crystals" exhibit an orientationally disordered phase beneath their melting point, and take a normal crystalline state at lower temperatures. An orientationally disordered phase is a state in which molecules remain at their lattice points but are oriented randomly. In this study, we obtained detailed knowledge about the molecular behavior during the phase transition of plastic crystals, specifically the occurrence of a high concentration of intrinsic defects, using terahertz spectroscopy and other techniques. We were also able to observe and evaluate in detail the introduction of defects due to the doping of impurities. Furthermore, it was newly discovered that camphorquinone is a plastic crystal.

Free Research Field

物性学

Academic Significance and Societal Importance of the Research Achievements

ここ数年，柔粘性結晶は，その巨大圧力熱量効果を利用した新たな冷媒としての応用への期待が高まっている．本研究の成果は，そのような応用に際し，材料としての柔粘性結晶の性能や安定性の評価に有効な方法を提供する．また，柔粘性結晶への不純物添加あるいは混晶化による改質の足掛かりとなる知見を含んでおり，テラヘルツ分光がその評価にも有効であることを示している．