Direct evidence of mesoscopic dynamic heterogeneities at the surfaces of ergodic ferroelectric relaxors

Spatial variability of polarization relaxation kinetics in the relaxor ferroelectric 0.9Pb (Mg1/3 Nb2/3) O3 -0.1 PbTiO3 is studied using time-resolved piezoresponse force microscopy at room temperature. Both the statistical principal component and correlation function analysis and the stretched exponent fits of relaxation curves illustrate the presence of mesoscopic "fast" and "slow" 100-200 nm regions. The spatial distribution of activation energies is reconstructed using a neural-network-based inversion of the relaxation data. The results directly prove the presence of mesoscopic heterogeneities associated with static and dynamic components of the order parameter on the surfaces of ferroelectric relaxors in the ergodic phase.