Atomic-Scale Imaging and Quantification of Electrical Polarisation in Incommensurate Antiferroelectric Lanthanum-Doped Lead Zirconate Titanate



Lanthanum doping of zirconium rich lead zirconate titanate gives rise to incommensurate, long-period antiferroelectric structures. The structure of two stacking sequences in this incommensurate phase is determined using quantitative analysis of high-resolution scanning transmission electron microscopy images, with the lead atom positions located with an exceptional precision of about 6 pm. This allows the estimation of local polarisation variations across the stacking units, and the polarisation varies in an approximately sinusoidal fashion along the stacking direction. The measured peak Pb atom displacements of about 28 pm and peak polarisation values of about 60 μC cm−2 match extremely well to reported values for the commensurate antiferroelectric PbZrO3 phase.