Domain fluctuations in a ferroelectric low-strain BaTiO₃thin film

The intriguing prospect of ferroelectric materials is that they possess spontaneous electric polarization that can be altered with applied electric fields, enabling numerous device applications including non-volatile memories, actuators, and sensors. Ferroelectric domain reconfiguration plays an important role in manipulating polarization switching behavior and the dynamical properties of the ferroelectric thin films. In this study, we utilized X-ray photon correlation spectroscopy to probe ordered a/c domain dynamics and fluctuations across a/b to a/c domain transformation and Curie temperature. Our studies show that the a/b to a/c domain transformation is accompanied by a decrease in fluctuation timescales, and an increase in intensity and correlation length. Surprisingly, domain fluctuations are observed up to 25 °C above the transformation, concomitant with the growth of a/c domains and coexistence of both domain types. A further increase in temperature brings the system closer to the Curie temperature resulting in the observance of a/c domain fluctuations. The observed time evolution and reconfiguration of domain patterns highlight the role played by phase coexistence and elastic boundary conditions in altering fluctuations timescales in ferroelectric thin films.