Dielectric permittivity and conductivity of amorphous PbTiO3

The DC and AC conductivities and dielectric properties of PbTiO3 in amorphous and crystallized states have been studied within a temperature range of 20–680°C. The anomaly in the ϵ′(T) dependence for amorphous state was found in the vicinity of a temperature corresponding to ferroelectric transition of crystalline lead titanate (TC ≅ 500°C). The anomaly appearance is a result of structural softening near crystallization temperature Tcr ≅ 600°C as well as a result of intrinsic ferroelectric phase transitions in relict crystalline regions. Long-term annealing above Tcr leads to an pronounced increase in ϵ′ and shaping of ϵ′ peak at 500°C, indicating the ferroelectric phase transition. The change from hopping to energy band mechanism of conductivity occurs as a result of thermal annealing of amorphous PbTiO3.