Observation of natural domain structure in ferroelectric superlattices by Piezoresponse Force Microscopy

Abstract

In this work, an investigation of the natural domain structure of superlattices of PbTiO3 with CaTiO3 or SrTiO3 at various volume fractions is presented. Superlattices were grown on SrTiO3 substrates via off-axis magnetron sputtering. The first indication of domain structure was found by X-ray diffraction. The naturally occurring domain structures are a priori not visible in Piezoresponse Force Microscopy (PFM) images of the surface taken with an Atomic Force Microscope (AFM). A custom-developed sequence of PFM lithography (i.e. writing patterns of polarization) and subsequent scans allows imaging of the natural domain structure and domain walls on the scale of tens of nanometers. This is the first time that real space images of this extremely fine domain structure have been obtained using PFM.