Abstract
The dielectric permittivity function of the ferroelectric materials Rochelle salt, TGS, ${\mathrm{BaTiO}}_{3},$ KDP, and ${\mathrm{LiTaO}}_{3}$ was measured in the frequency range 1 mHz--1kHz. The measurements were done both above and below the ferroelectric transition, except for ${\mathrm{LiTaO}}_{3},$ in which the highest measurement temperature was 146 \ifmmode^\circ\else\textdegree\fi{}C. In the first four crystals, the dielectric function shows a central peak of width less than 1 Hz which disappears completely in the paraelectric phase. There are good indications that the central peak involves the diffusion of the heat generated by pyroelectric effect, but the pyroelectric coupling is not enough to account for the dispersion step. Switching of small polarization clusters with the exciting electric field is suggested to be a source of the enhanced central peak intensity. In ${\mathrm{LiTaO}}_{3},$ a Debye relaxation of the polarization was observed, with relaxation time decreasing very quickly with increasing temperature. That relaxation is perhaps related to a central peak observed in light scattering in the 1970's.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.