**Author details**

#### Toshio Ogawa

of DC poling on elastic constants in single crystal and ceramics through our investigation of the measurement on sound velocities. From this figure, it is clearly understand between single and oriented domains in single crystal, and the relationships between size dimensions, domain and grain alignments, and the effect of DC poling on elastic constants in piezoelectric materials.

**Figure 19.** Relationships between domain alignment, size dimensions, piezoelectricity, and effect of DC poling on elas‐

Roles of domain and grain boundaries in relaxor single-crystal plates and ceramics were clarified by measuring sound velocities. Effect of domain boundaries on elastic constants was evaluated by the effect of DC poling on elastic constants in (100)0.70Pb(Mg1/3Nb2/3)O3– 0.30PbTiO3 relaxor single-crystal plates. Effect of grain boundary on elastic constants was evaluated by comparing elastic constant in the relaxor single crystals and the ceramics. Finally, the different origins of piezoelectricity in single crystals and ceramics were proposed through

This work was partially supported by two Grants-in-Aid for Scientific Research C (Nos. 21560340 and 26420282), a Grant from the Strategic Research Foundation Grant-Aided Project for Private Universities 2010–2014 (No. S1001032) from the Ministry of Education, Culture,

tic constants in single crystal and ceramics.

our investigation of the measurement on sound velocities.

**5. Summary**

58 Piezoelectric Materials

**Acknowledgements**

Address all correspondence to: ogawa@ee.sist.ac.jp

Department of Electrical and Electronic Engineering, Shizuoka Institute of Science and Technology, Fukuroi, Shizuoka, Japan
