Three-dimensional ferroelectric domain imaging of bulk Pb(Zr,Ti)O3 by atomic force microscopy

Abstract

We report on the ferroelectric domain evolution as a function of the depth of the surface of 100 μm thick bulk Pb(Zr,Ti)O3 (PZT) doped with 2% Nb. Ferroelectric domain imaging (FDI) was performed by piezoelectric detection assisted by atomic force microscopy (AFM). The depth evolution of the polarization orientation was obtained by repeated surface chemical etching followed by FDI. It was observed that backswitching mainly occurred close to 90° domain and grain boundaries. The depth of these domains was estimated to be about 500 nm. This indicates that nonpenetrating domains of opposite polarity can retain their polarization vector near the surface region without the help of a top electrode interface. It also supports the idea that they act as preferential nucleation sites for polarization reversal. We suggest that AFM FDI combined with proper etching methods could be used to construct a three-dimensional image of the whole domain structure by stacking two-dimensional images layer by layer.