field and the determination of the piezoelectric coefficient for different crystalline orientations.
Butterfly loops demonstrate the piezoelectric hysteresis in the material while the fact that the loops are not closed indicate the existence of a selfpolarization.
The experiment further addresses the piezoelectric anisotropy: the piezoelectric coefficient is about a factor two larger in the [100] than in the [110] direction.
These studies pave the way to novel research on the origin of the self-polarization effect in thin films as a function of their thickness and their composition.
Moreover, future synchronous experiments in combination with AC electric fields may allow for dynamic measurements giving access to the reorientation of the Acknowledgments