High Piezoelectricity in Sustainable Materials from Viewpoints of Elastic Constants

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420282
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Shizuoka Institute of Science and Technology
• Principal Investigator: Ogawa Toshio 静岡理工科大学, 理工学部, 教授 (40247573)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 圧電性の起源 / 弾性定数 / ドメインバウンダリー / 結晶粒界 / リラクサ圧電単結晶 / 圧電セラミックス

Outline of Final Research Achievements

Sound velocities were measured in single-crystals and ceramics using an ultrasonic precision thickness. It was possible to evaluate effects of domain and grain boundaries on elastic constants. Existence of domain boundaries in single crystal affected the decrease in all of the elastic constants by DC poling. The existence of grain boundaries affected the decrease in Young’s modulus and rigidity and the increase in Poisson’s ratio and bulk modulus. These phenomena come from domain alignment by DC poling, and both the boundaries act as to absorb mechanical stress by defects due to the boundaries.
The origin of piezoelectricity in single crystals is caused by low bulk modulus and Poisson’s ratio, and high Young’s modulus and rigidity in comparison with ceramics. On the contrary, the origin of piezoelectricity in ceramics from viewpoints of ceramic grain orientation is caused by high Poisson’s ratio by high bulk modulus, and low Young’s modulus and rigidity due to domain alignment.

Free Research Field

工学