Preparation of Potassium Niobate Crystals with Fine Engineered Domain Configurations and Their Enhanced Piezoelectric Properties

Potassium niobate (KNbO ₃ ) single crystals were grown by a top-seeded solution growth (TSSG) method. At first, the electric field was applied along [001]_c (cubic notification system) direction of KNbO ₃ crystals to induce the engineered domain configurations into KNbO ₃ crystals. Prior to domain engineering, the piezoelectric properties of [001]_c oriented KNbO ₃ single-domain crystals were measured. These measurement values were completely consisted with the calculated d ₃₁ and d ₃₂ . Finally, the fine engineered domain configurations were induced into KNbO ₃ crystals. As a result, piezoelectric properties increased with decreasing domain sizes of the engineered domain configuration. However, the symmetry of the KNbO ₃ crystals was, and there were four kinds of domain structures such as 90°, 180°, 60° and 120° domains. Thus, the engineered domain structure induced in this study was very complicated structure, and the piezoelectric properties were also depended on domain pattern and kinds of domain walls.

Keywords:

• Domain engineering
• potassium niobate
• single crystals
• engineered domain configurations

PACS numbers:

• 77.65.Bn
• 77.80.Dj
• 77.84.Dy

Acknowledgments

We would like to thank Dr. S.-E. “Eagle” Park, Dr. T. R. Shrout and Dr. L. E. Cross of MRL, PennState University for their helpful suggestion and discussion about the engineered domain configurations. Moreover, we also would like to thank Dr. J. Erhart of ICPR, Technical University of Liberec for his helpful discussions about the analysis of the domain configuration and calculation. This study was partially supported by (1) a Grant-in-Aid for Scientific Research (16656201) from the Ministry of Education, Culture, Sports, Science, and Technology, Japan, (2) the Japan Securities Scholarship Foundation, (3) Toray Science Foundation, (4) the Kurata Memorial Hitachi Science and Technology Foundation, (5) Electro-Mechanic Technology Advanced Foundation, (6) Tokuyama Science Foundation and (7) Yazaki Memorial Foundation for Science and Technology.