Specifics of polarisation switching in PbNi1/3Nb2/3O3–PbTiO3–PbZrO3 ferroelectric ceramics

The growing interest in disordered relaxor ferroelectrics is due to unusual properties mainly related to the existence of broad phase transitions characteristic to the systems. The effects of bias field on the dielectric response and polarisation switching are studied in the 0.5 PbNi 1/3 Nb 2/3 O 3 – x PbTiO 3 –(0.5− x ) PbZrO 3 system at different PbTiO 3 :PbZrO 3 ratio. Thermal behaviour of normalised remnant polarisation P r / P max of compositions with content of lead titanate x =0.33 and x =0.35 at frequency 0.1 Hz and different values of field E o are measured. Results of measured polarisation and depolarisation currents are compared with characteristics of polarisation switching. In the case of composition with x =0.33 the value of P r / P max does not depend on the field amplitude in the range 4–10 kV/cm within the thermal interval from 50 to 135 °C. In composition with x =0.35 the interval of P r / P max independent of E o (5–10 kV/cm) is observed closer to the temperature of dielectric permittivity maximum T m ≈180 °C