0000000000255806
AUTHOR
Jonas Grigas
Radio and Microwave Spectroscopy of 0.2PMN-0.4PSN-0.4PZN Relaxor Ceramics
Dielectric spectroscopy results of 0.2PbMg 1/3 Nb 2/3 O 3 -0.4PbSc 1/2 Nb 1/2 O 3 -0.4PbZn 1/3 Nb 2/3 O 3 ceramics are reported for 200 < T < 450 K and 20 Hz < v < 11 GHz. Dielectric constant is very high (more than 12000) in the vicinity of the peak. Anomalous broad dielectric relaxation has been observed near and below the temperature of the maximum permittivity, T m (at 1 kHz). The distribution of relaxation times have been calculated directly from the dielectric spectra. At higher temperatures than the maximum permittivity, T m the distribution of the relaxation times is symmetrically shaped (Cole-Cole function satisfactory describes the dielectric response). At lower temperatures, the …
Distribution of the relaxation times of the new relaxor 0.4PSN–0.3PMN–0.3PZN ceramics
Abstract The real distribution function of the relaxation times g ( τ ) of the relaxor ferroelectric ceramics 0.4PSN–0.3PMN–0.3PZN is calculated from the experimental dielectric spectra obtained in the frequency range from 20 Hz to 1.25 GHz. Below the Burns temperature T B ≅ 380 K, where the clusters begin to appear on cooling, the distribution of the relaxation times is symmetrically shaped. On cooling, the permittivity and loss spectra strongly broaden and slow down. The g ( τ ) function becomes asymmetrically shaped and the second maximum appears. The width of the g ( τ ) function is calculated at different temperatures. The shortest relaxation time is of the order of 10 −12 s and it r…