POLAR STRUCTURES OF PbMg1/3Nb2/3O3-PbTiO3 RELAXORS: PIEZORESPONSE FORCE MICROSCOPY APPROACH

Relaxor ferroelectrics are one of the mysterious objects of the solid-state physics studied over 50 years. The physical properties of relaxors were mainly assessed by scattering and dielectric methods and revealed the importance of polarization correlations with the short-range order, so-called polarization nanoscale regions. This paper review recent progress achieved by using piezoresponse force microscopy (PFM) to analyze the spatial distribution of polarization and its evolution with time, temperature, and electric field for the most popular relaxor family: solid solutions between PbMg1/3Nb2/3O3 and PbTiO3. The PFM technique has proved to be a powerful tool for the investigation of local properties of relaxors where optical techniques obviously fail because of their lack of resolution. The PFM study of relaxors clearly helps to understand the mechanism of polarization distribution and illustrates the importance of mesoscopic polarization patterns that were until now overlooked by major theories of the relaxor state.