Observation of ferroelectric polarization in the noncontact mode of a scanning nonlinear dielectric microscope

This paper describes the performance of a scanning nonlinear dielectric microscope when a gap exists between the specimen and the probe of the microscope. First, a theory for the sensitivity of the scanning nonlinear dielectric microscope as a function of the gap height is described. Second, using the microscope in a noncontact mode, an area scan of the polarization of an alternately poled ferroelectric thin film of a copolymer consisting of vinylidene fluoride and trifluoroethylene is carried out.