Large piezoelectric effect and low-field and high-speed response in electronic dielectrics

2015 Fiscal Year Final Research Report

• Project/Area Number: 26630315
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials/Physical properties
• Research Institution: Kyoto University
• Principal Investigator: Tanaka Katsuhisa 京都大学, 工学(系)研究科(研究院), 教授 (80188292)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 電子誘電体 / 圧電性 / 強誘電性 / 圧電応答顕微鏡 / 単結晶 / 多結晶 / 相転移

Outline of Final Research Achievements

It has been suggested that ferroelectricity and/or piezoelectricity presumably occurs in RFe2O4, where R is the rare-earth or In, one kind of the electronic dielectrics. Nonetheless, the mechanism to lead to the ferroelectricity is unclear. The present study is aimed at clarifying the phase transition of single-crystalline YFe2O4 and TmFe2O4 by examining the temperature dependence of polarization and piezoelectric strain with piezoelectric force microscopy. A hysteresis loop is clearly observed in the relation between polarization and voltage at room temperature to 80℃. In the voltage dependence of strain, a so-called butterfly curve is found in the same temperature region. On the other hand, both the hysteresis loop and the butterfly curve disappear when the measurement temperature is above 90℃. The experimental fact unambiguously indicates that the two compounds undergo the phase transition between ferroelectric and paraelectric states at around 80 to 90℃.

Free Research Field

無機固体化学