Scanning nonlinear dielectric microscopy with nanometer resolution

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 of the domains in PZT and SBT thin films. Especially in a film measurement, the resolution was sub-nanometer order. Next, we also demonstrate that the resolution of SNDM is higher than that of a conventional piezo-response imaging. Finally, to check the performance of the SNDM system as a ferroelectric recording system, we conducted a fundamental study on the writing of domain inversion dot in PZT thin film and succeeded to have a very small domain dots with the size of 25 nm.