Ti-induced and modified dielectric relaxations in PbZr_1-xTi_xO₃ single crystals (x<or=0.03) in the frequency range 10 Hz-10 MHz

Three relaxation processes for frequencies from 10 Hz to 10 MHz and for various Ti concentrations in PbZr_1-xTi_xO₃ (x<or=0.03) are presented. The lowest relaxation process (below 100 Hz in the paraelectric phase) is attributed to electrochemical processes contributing to the dielectric polarization. The second is strong low-frequency dipolar relaxation (up to 1 kHz in the paraelectric phase) which has a nearly monodispersive character and is related to the disorder in the oxygen sublattice. While for pure PbZrO₃ the contribution of the dielectric step Delta in , coming from this relaxation, to in '(T) was temperature independent, for PbZr_1-xTi_xO₃ it becomes a function of temperature. The third relaxation in the range of a few kilohertz visible in the transient phase and above T_c appears because of Ti introduction and comes from the interface dynamics of the polar regions in the paraelectric phase and motion of the domain walls in the intermediate phase of ferroelectric properties.