Anisotropy of electric field freezing of the relaxor ferroelectric Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$
Zdravko Kutnjak, B. Vodopivec, and Robert Blinc

The ferroelectric $E-T$ phase diagram of relaxor ferroelectrics depends on the way the ferroelectric transition lines are approached. Here we present the $E-T$ phase diagram of relaxor PMN where the temperature was held constant and the electric dc bias field applied along the [111] and [001] directions was varied. Strong anisotropy was observed for both directions. For the [111] direction, the critical point was shown to exist at practically the same field as in the $E$ = const., $T$ = variable case whereas no critical point could be determined for the [001] direction for $|E_{bias}|&lt20$ kV/cm. When the electric field was applied along the [111] direction a strongly non-linear first-order type jump in the polarization due to the cooperative ordering transition was observed. In the [001] direction, on the other hand, only a smooth field dependences of the polarization was found indicating the lack of cooperative ordering.

© 2008 The American Physical Society.