Nonlinear dielectric response in partially resonant composites with radial dielectric anisotropy

The effective nonlinear dielectric response of a dilute (or nondilute) suspension of coated cylinders is investigated. The coated cylindrical inclusions consist of nonlinear core and linear anisotropic dielectric shell. By taking into account the radial dielectric anisotropy, new partial resonant conditions are derived to be sϵsr0+ϵh0=0 or sϵsr0+ϵc0=0 (ϵc0, ϵh0 are the linear dielectric functions of the core and the host medium, while ϵsr0 and ϵst0 (s≡ϵst0/ϵsr0), are the radial and tangential dielectric function of the shell respectively). Under partial resonant conditions, without changing the external potential, the coated cylinders can be replaced by the solid ones with larger nonlinear susceptibility and volume fractions than those of original cylindrical cores. As a result, the effective nonlinear dielectric response χeχe of the partially resonant systems may be greatly enhanced. Analytical results show that χeχe is in proportional to 1/λ2(s+1)1/λ2(s+1) (λ is the interfacial parameter ranging from 0 to 1). Therefore, increasing dielectric anisotropy s   results in further enhancement of χeχe. We conclude that the partially resonant composites with radially dielectric anisotropy can be served as a new kind of nonlinear dielectric materials.