Scanning nonlinear dielectric microscopy with nanometer resolution

A very high-resolution scanning nonlinear dielectric microscope (SNDM) 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 of the domains in PZT thin film. Especially in a film measurement, the resolution was sub-nanometer. Next, we also demonstrate that the resolution of SNDM is higher than that of a conventional piezo-response imaging. Finally, we conducted a fundamental study on the writing of a domain inversion dot in PZT thin film and succeeded to have a very small domain dots of the size 25 nm.