Influences of d.c. and a.c. fields on the dielectric properties of relaxorferroelectric ceramics

The influence of direct and alternating current fields on the dielectric pr operties of PMN-PZN-PT relaxor ferroelectric ceramics is examined. The redu ction of both dielectric constant and dielectric loss by the applied d.c. b ias field was demonstrated. An opposite trend was observed on the a.c. fiel d dependence of dielectric response. The analysis revealed that d.c. bias r educes the degree of frequency dispersion, whereas a.c. drive increases it linearly. It is shown that the results obtained are consistent with the pre dictions of the glass model employing the concept of slow dipoles and froze n dipoles.