Scanning nonlinear dielectric microscope

This article describes a new scanning technique for imaging the state of spontaneous polarization of a ferroelectric material by measuring the microscopic point-to-point variation of its nonlinear dielectric constants. First, the theory for detecting polarization is described. Second, the technique for measuring the nonlinear dielectric response is described. Finally, using this new microscope, area scans are obtained of the polarization of poled lead zirconate titanate ceramics, a lithium niobate single crystal, and of piezoelectric thin films of the copolymer of vinylidene fluoride and trifluoroethylene.