Theory of nonlinear ac responses of inhomogeneous two-component composite films

Chemical deposition techniques as well as diffusing techniques can be used to produce inhomogeneous composite films. We put forth a theory to investigate the nonlinear ac responses of a model graded film. We find that the responses are strongly dependent on the gradation profile and the thickness of the film, due to the local field effect. Thus, it seems possible to real-time-monitor the gradation profile and the thickness of the film by measuring the nonlinear ac response of inhomogeneous composite films.