Effective medium approximation for flicker noise and weak nonlinearities in composite media

An unambiguous formulation of the self-consistent effective medium approximation (SEMA) is presented and then applied to the problem of flicker noise in a composite conductor where each component has a small nonlinear (power law) correction to the Ohmic conductivity. The results, while reasonable for dilute systems, lead to seemingly strange results (e.g., infinite flicker noise and infinite nonlinear conductivity) for a nondilute metal-insulator mixture. These are explained in terms of the special microstructure for which SEMA is exact and demonstrate the great sensitivity of flicker noise and nonlinear conductivity to microstructural details.