Dielectric dispersion of lead hafnate crystals in the low frequency regime

The low frequency dispersion (for f = 5 to 1000 Hz) of the dielectric permittivity on PbHfO3 crystals is investigated. Data analysis is based on the two-layer capacitor model. For the paraelectric phase, the following values of surface layer parameters are obtained: permittivity epsilon = 4 to 15, conductivity 5.6 x 10(-8) to 2.2 x 10(-6) Omega(-1) m(-1). The bulk dielectric permittivity of the crystal changes from 2850 at 210 degrees C to 2100 at 250 degrees C.