Dielectric spectroscopy and distribution of relaxation times of PMN-PSN ceramics

Abstract

The complex dielectric permittivity of 0.05PMN-0.95PSN ceramic was measured in the frequency range from 20 Hz to 3 GHz. Two anomalies of complex dielectric permittivity were observed 398 and 286 K which can be attributed to the ferroelectric and antiferroelectric phase transitions respectively. From frequency dependences of the real and imaginary parts of dielectric permittivity the distribution of relaxation times f(τ) was calculated. The distribution of relaxation times data together with the dielectric dispersion data shows the competing interactions between these two phase transitions and appearance of the dipolar glass state below the antiferroelectric phase transition.

Soft mode in PMN–PSN ceramics

“…The critical temperature T cr in ferroelectric PMN-PSN ceramics is much lower than the critical temperature in PMN-PSN relaxors. In ferroelectric PSN-PMN the critical temperature T cr roughly corresponds to ferroelectric phase transition temperature [5,19]. In 0.2PSN-0.8PMN relaxor T cr is very high and, similar to other relaxor perovskites [11], corresponds to the Burns temperature.…”