Polarization switching in (001 )-oriented Pb(Mg 1/3Nb 2/3)O 3-x%PbTiO 3 crystals: Direct observation of heterogeneous nucleation by piezoreponse force microscopy

Abstract

Polarization switching in (001)-oriented Pb(Mg 1/3Nb 2/3)O 3-x%PbTiO 3, PMN-x%PT, crystals for x=20 and 35 has been investigated in situ by scanning force microscopy in a piezoresponse mode, under a step-increased dc electrical voltage (V dc). The results demonstrate that switching initiates by the nucleation of nanosized polar regions with a reversed polarization. For x=20, nucleation occurs heterogeneously throughout the volume of the crystal. However, with increasing PT content, nucleation tends to preferentially initiate near preexisting twin boundaries; with increasing V dc, the domains becoming increasingly "diffuse" due to heterogeneous nucleation and growth throughout the crystal. © 2004 American Institute of Physics.