Field and frequency dependence of the dielectric response of Zr-rich PZT at the FRL-FRH and FRH-PC phase transitions

Dielectric permittivity and dielectric losses have been investigated in Zr rich Pb (Zr1-xTix)(1-y) NbyO3 (x = 0.035 +/- 0.005, y = 0.039 +/- 0.013) at the F-RL - F-RH and the F-RH - Pc phase transitions for three frequencies (1, 100, 500 kHz) and three a.c. field amplitudes (7.3, 21.8, 65.5 V/cm). The frequencies investigated are sufficient to show the presence of three different phenomena: ionic conductivity, domain wall dielectric relaxation, not well described with these data, and piezoelectric resonances. The dependence of the dielectric response with temperature and field near both transition are reported in the vicinity of both phase transitions.