Enhanced piezoelectric properties of piezoelectric single crystals by domain engineering

Various engineered domain configurations were induced into barium titanate (BaTiO3) single crystals, and their piezoelectric properties were investigated as a function of (1) the crystal structure, (2) the crystallographic orientation and (3) the domain size. As a result, the orthorhombic mm(2) BaTiO3 crystals showed the highest piezoelectric properties among three kinds of BaTiO3 crystals such as tetragonal 4mm, orthorhombic mm(2) and rhombohedral 3m phases. On the other hand, the [001], oriented BaTiO3 crystals always exhibited the larger piezoelectric properties than the [111], oriented BaTiO3 crystals. Moreover, the domain size dependence on the piezoelectric properties was discussed, and this result revealed that the piezoelectric property was strongly dependent on the domain size, i.e., the piezoelectric properties significantly increased with decreasing domain size. On the basis of the above results, the most suitable engineered domain configuration was proposed for the high-strain high-coupling piezoelectric application.