Scanning nonlinear dielectric microscopy for investigation of nano-sized ferroelectric domains and local crystals anisotropy

A very high-resolution scanning nonlinear dielectric microscope with nanometer resolution was developed for the observation of ferroelectric polarization. We demonstrate that the resolution of the microscope is of a nanometer order by measurement of the c - c domain wall of a BaTiO₃ single crystal, and that this microscope is very useful not only for the domain observation of ferroelectric bulk material but also for that of thin films. Finally, it is also demonstrated that this microscopy is very useful for a local crystal anisotropy like the crystal orientation of thin films by measuring polarities of ZnO thin film on LiNbO₃ and LiTaO₃ single crystal substrates.