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 vB/vG (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.