Imaging of ferroelectric films under an applied electric field by scanning electron microscopy

摘要

We report on scanning electron microscopy (SEM) measurements under external electric fields as a tool for studying electric-field-induced processes in ferroelectric thin films. Epitaxial films of BaTiO_3, grown by metal-organic chemical-vapor deposition on MgO substrates, served as samples in this research. Electric fields of up to 6 MV/m were applied to interdigital electrodes having 5 μm blank intervals between metallic strips deposited on the top of the films. In situ SEM measurements under applied electric fields revealed time-dependent variations in contrast, attributed to domain rearrangements. The results obtained are analyzed in terms of nucleation and growth of energetically favorable domains. The critical electric field of about 10 MV/m for the 90°-domain flips deduced from these measurements is in agreement with previously published data.