Large piezoelectricity and dielectric permittivity in BaTiO3-xBaSnO3 system: The role of phase coexisting
Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology,
Xian Jiaotong University - Xi'an 710049, China
2 Ferroic Physics Group, National Institute for Materials Science - Tsukuba 305-0047, Ibaraki, Japan
Accepted: 26 March 2012
We report ultrahigh dielectric and piezoelectric properties in BaTiO3-xBaSnO3 ceramics at its quasi-quadruple point, a point where four phases (Cubic-Tetragonal-Orthorhombic- Rhombohedral) nearly coexist together in the temperature-composition phase diagram. At this point, dielectric permittivity reaches ∼75000, a 6–7-fold increase compared with that of pure BaTiO3 at its Curie point; the piezoelectric coefficient d33 reaches 697 pC/N, 5 times higher than that of pure BaTiO3. Also, a quasi-quadruple point system exhibits double morphotropic phase boundaries, which can be used to reduce the temperature and composition sensitivity of its high piezoelectric properties. A Landau-Devonshire model shows that four-phase coexisting leading to minimizing energy barriers for both polarization rotation and extension might be the origin of giant dielectric and piezoelectric properties around this point.
PACS: 77.22.-d – Dielectric properties of solids and liquids / 77.65.Bn – Piezoelectric and electrostrictive constants
© EPLA, 2012