High pressure treated ZnO ceramics towards giant dielectric constants

Abstract

ZnO ceramics with giant dielectric constants have been synthesized via a high pressure treating method. SEM results reveal that the ceramics using high pressure treated powders are porous, and the dielectric constant of the specimens first increases and then decreases with increasing density. Ceramics sintered at 1050 °C possess the optimal giant room temperature dielectric constants (∼1.8 × 10⁴ at 100 Hz) with low relative density and dielectric loss. The improved dielectric constant can be attributed to enhanced Maxwell–Wagner poly-dispersive relaxation due to the high pressure treating process, which makes ZnO porous ceramics a potential material for high dielectric constant applications. This approach is generic and provides a new avenue to obtain porous ceramics with excellent dielectric properties.