Contribution of Relaxation Effect to the Permittivity of Mg_1-xZn_xTiO₃ Ceramics

This work reported the investigation on the effect of relaxation to the permittivity (′ _r ) characteristic of Mg_1-xZn _x TiO₃ ceramics for x = 0 - 0.5 (MZT0 - MZT0.5) measured from 1 Hz to 330 MHz. Within that frequency range, the relaxation effect that consists of the space charge (SC) and the dipolar (D) polarization mechanisms were identified. The contribution of the D relaxation in MZT0 - MZT0.2 systems extents overall from about 100 Hz to 330 MHz, while that in MZT0.3 - MZT0.5 systems is from 50 kHz to 330 MHz. The remaining frequencies, i.e. from 1 to 90 Hz for MZT0 - MZT0.2 and from 1 Hz to 50 kHz for MZT0.3 - MZT0.5, are attributed to the SC relaxation. The D polarization mechanism provides constant ′ _r values which vary from (15.4 - 17.0) ± 0.3 throughout the samples. Contribution of the SC polarization mechanism to the characteristic is supported by the simultaneous presence of different content and level of resistivity of the secondary phase of (Mg_1-αZnα)₂TiO₄ in MZT0 - MZT0.2 systems and of (Zn_1-αMgα)₂TiO₄ in MZT0.3 - MZT0.5, along with the presence of the main Mg_1-xZn _x TiO₃ phase, as a result of the variation of zinc content in the systems.