Relization of giant piezpelectric response induced by polarization rotation

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K14119
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials/Physical properties
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Masaki Azuma 東京工業大学, 科学技術創成研究院, 教授 (40273510)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: Polarization rotation / Piezoeelctric material / giant c/a / BiFeO3

Outline of Final Research Achievements

In this study, we fabricated high-quality cobalt-substituted BiFeO3 epitaxial thin films with a giant c/a ratio by pulsed laser deposition, and systematically studied the relationship between the crystal structure and the piezoelectric responses. From crystal structure analysis, we found that all the BFCO thin films had a giant c/a ratio (1.2-1.3) same as the bulk phase and the crystal structure underwent successive transitions from MC-type monoclinic phase (x= 0-0.15) to MA-type monoclinic phase (x= 0.15-0.30), and finally to tetragonal phase (x= 0.50) with increasing Co content x. The MA phase is essentially the same as that found in the bulk BFCO where polarization rotation has been confirmed. From piezoelectric measurements, we found that the responses were enhanced in the MA phase. This indicates that polarization rotation does play a crucial role to realize improved piezoelectric responses in this material.

Free Research Field

固体化学