GRAIN-SIZE DEPENDENCE OF DIELECTRIC-CONSTANT FOR MODIFIED (PB0.63BA0.37)(ZR0.7TI0.3)O3 CERAMIC MATERIAL

The grain size dependence of the dielectric constant for a modified (Pb0.63Ba0.37)(Zr0.7Ti0.3)03 material from approximately 55-degrees-C to 150-degrees-C has been studied. Grain sizes in the range of 1.2 mum to 7.0 mum were prepared by varying the sintering temperature and time. The maximum dielectric constant decreased monotonously as the grain size decreased. The dielectric constant at a lower temperature for the ferroelectric phase (-55-degrees-C) also decreased monotonously. However, at a high temperature for the cubic phase (150-degrees-C), the dielectric constant was almost constant. This monotonous decrease of the dielectric constant at a lower temperature is the same phenomenon as for the Pb(Mg1/3Nb2/3)O3 material. The Curie temperature of the ceramic shifted toward a higher temperature as the grain size was reduced. However, the aging rate was almost independent of the grain size.