Crystal structural study of ferroelectrics to reveal the phase-transition mechanism from the view point of electronic state of ferroactive ions

2015 Fiscal Year Final Research Report

• Project/Area Number: 26600086
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Crystal engineering
• Research Institution: Hiroshima University
• Principal Investigator: Kuroiwa Yoshihiro 広島大学, 理学(系)研究科(研究院), 教授 (40225280)
• Co-Investigator(Kenkyū-buntansha): WADA SATOSHI 山梨大学, 総合研究部, 教授 (60240545)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 誘電体物性 / ペロブスカイト / Ｘ線回折 / 放射光 / 電子密度

Outline of Final Research Achievements

Valence electron density studies are carried out by synchrotron radiation X-ray diffraction to find an analogical indicator which points to the phase transition temperature in ferroelectrics, mainly with a perovskite-type (ABO3) structure, purely only from the information of their crystal structures. In the case that a ferroactive ion with the d0-ness electron configuration is located at the B-site, we have revealed that there is a close relation between the phase transition temperature and the covalency on the B-O bonding. In the case an ion with the lone electron pairs at the A-site, the ion shows a specific thermal motion. Direct experimental evidence is obtained that the A-site ion drives a lattice distortion like a ferroactive ion.

Free Research Field

構造物性