Thickness dependence of ferroelectric properties of modified lead titanate ceramics

Abstract

Using a pulse sequence method, switching currents in Ca modified lead titanate ceramics have been measured. Slices in the hundred micron range were used.

It has been found that the threshold switching voltage depends on thickness as dⁿ, with n<1. The switching time dependence on applied field (for both signs) and thickness have also been determined: they follow laws of types E⁻ⁿ and dⁿ with (n>0).

The asymmetric effect found in the switching currents has been explained as due to the internal field produced by space charge, which should be dependent on the ratio v_B/v_G (volume of grain boundary / volume of grain).

The amount of 90° domains back-switched after the first pulse has been calculated and the dynamic of relaxation has also been established.