Quantitative microscopy of nonlinear dielectric constant using a scanning evanescent microwave microscopy

Quantitative characterization of dielectric nonlinearity in ferroelectric materials has been successfully performed using a scanning evanescent microwave microscope, and a key calibration coefficient for quantitative microscopy of nonlinear dielectric constant is derived. This unique technique has advantages of high spatial resolution and simultaneously accessing of other related properties such as dielectric constant and magnetoelectric coefficient. Samples of LiNbO₃ single crystal and PbTiO₃ thin film are measured, which demonstrates that this technique can access the nonlinear dielectric constant of a microregion with a sensitivity of 1.0×10^-21 F/V.