The Dynamics of Domain Walls Determined from Acoustic Emission Measurements

Abstract

The field-induced jump-like dynamics of a single planar domain wall in single crystalline uniaxial ferroelectric-ferroelastic Gd 2 (MoO 4 ) 3 and needle domains in the perovskite BaTiO 3 are compared. Acoustic emission as well as ferroelectric Barkhausen pulse measurements were performed in order to investigate time coincidences with optically observed jumps. In both crystals significant amounts of acoustic emissions occur. The coincidences of both event types in Gd 2 (MoO 4 ) 3 are determined by the particular character of extended defects in the crystal and the relative orientation of the acoustic sensor. Hardly any Barkhausen pulses but huge amounts of acoustic pulses are observed for the annihilation of needle domains. The underlying microscopic mechanisms are discussed.