Ultrawide band dielectric spectra from kHz to THz were measured to investigate quantitatively the contributions of ionic and dipole polarizations to the ferroelectric phase transition in BaTiO3(BT) ceramics. Permittivity derived from ionic polarization (σionic) exhibited its maximum at the Curie temperature (Tc), attributing to the softening of the soft phonon mode. Permittivity derived from dipole polarization (σdipole) was nearly constant below the Tc, while σdipole remained above the Tcand σdipole increased on cooling, exhibiting its maximum near the Tc. The behavior in σdipole above the T ccould be interpreted as precursor phenomenon of ferroelectric phase transition and theσdipole above the Tcwas due to the local tetragonal type distortion in paraelectric phase.
ASJC Scopus subject areas
- General Engineering
- General Physics and Astronomy