Molecular activation and chemical conversion by dielectric property

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K19180
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials chemistry, Energy-related chemistry, and related fields
• Research Institution: The University of Tokushima
• Principal Investigator: YAMAMOTO Takashi 徳島大学, 大学院社会産業理工学研究部(理工学域), 准教授 (70361756)
• Project Period (FY): 2017-06-30 – 2019-03-31
• Keywords: 焦電結晶 / 積層型ユニット / 誘起高電場 / X線 / 物質変換

Outline of Final Research Achievements

Three types of stacked LiTaO3 single crystal units were assembled to investigate effects of shape of the single crystal and degree of ambient pressure on X-ray emission and discharge behavior based on the pyro electricity. Every instantaneous emission of visible light due to discharge occurred at the side of stacked crystals during heating and cooling cycle between room temperature and 400 K under atmospheric pressure. Discharge frequency on a stacked unit made of equal-sized four pieces (type-A) was five times more than that on a unit made of irregularly-sized pieces (type-C). Discharge occurred possibly at narrow gap between two pieces of plate-like single crystal. During heating process up to ca. 400 K under 1 or 0.0001 Pa, spike-like X-ray emission for a few seconds through one minute occurred repeatedly on both type-A and -C units. The maximum energy of emitted X-ray was independent on both degree of vacuum and shape of stacked plate-like LiTaO3 single crystal.

Free Research Field

触媒化学

Academic Significance and Societal Importance of the Research Achievements

LiTaO3単結晶が温度変化を与えるのみで高電位を自発的に生じる現象（焦電効果）について，単一厚さの単結晶を積層させることで自在に誘起される電圧を制御することが可能であることが確認され，焦電特性を利用した詳細な物性/開発研究をより容易に行うことが可能であることを示した．また本材料がキュリー温度との関係より知見が少ない473 K以上の領域でも20 kVもの電圧が発生することを示した．タンタル酸リチウムが低消費電力型高電場発生ユニットとして， 焦電特性を物質変換反応など新機能へ利用するための知見が得られた．