Low‐frequency dielectric dispersion in polymer‐derived amorphous silicon carbonitride ceramics

Abstract

The dielectric response of polymer‐derived amorphous silicon carbonitride (PDC‐SiCN) material was studied over a wide frequency range from 1 mHz to 10 MHz. Aside from presenting a relaxation process over 105 to 0.03 Hz frequency range, the material showed a strong low‐frequency dielectric dispersion (LFDD), which resulted in extremely high permittivities (up to 105) at frequencies lower than 0.03 Hz. It is identified that this LFDD resulted from relaxation process was not induced by conductivity. Therefore, PDC‐SiCN material showed two relaxation processes. Based on its microstructure, two polarization mechanisms were proposed for PDC‐SiCN: a mechanism based on polarons generated by unpaired electrons present in the material and an interfacial polarization mechanism as a result of different properties of SiCxN4−x matrix and free‐carbon clusters. Interfacial polarization process was simulated based on a parallel plate model involving two different materials. The result indicated that the relaxation time of an interfacial polarization can be distributed over a broad time range in the material.

Tailorable Dielectric Performance of Niobium‐Modified Poly(hydridomethylsiloxane) Precursor‐Derived Ceramic Nanocomposites

“…[ 18–20 ] The absence of dielectric loss peak in composites with low dielectric permittivity is probably owing to the negligible contribution of ε ′ toward any significant loss factor with frequency. [ 18 ] Moreover, the decrease in tan δ with increasing frequency is attributed to the limitation of hopping frequency of charge carriers to a certain frequency limit beyond which they cannot follow the changes in the externally applied electric field. However, the peak observed in the case of composites with high dielectric permittivity is the combination of energy dissipation mechanism such as DC conduction and interfacial polarization.…”

“…[1][2][3][4] In the last two decades, more than %650 articles have been published on CP materials (Figure 1a), exemplifying scientific and technological inquisitiveness toward the utilization of dielectric CP materials for energy storage applications. The performance index of dielectric materials and subsequent selection criteria can be based on dielectric permittivity (ε 0 ) and loss (tan δ) [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] as presented in the Ragone chart ( Figure 1b). CP values are exhibited by ferroelectric and antiferroelectric materials with moderate-to-high tan δ values.…”

“…[24,[26][27][28] Recently, low-frequency (<10 MHz) dielectric behavior of precursor-derived amorphous nonoxide silicon carbonitrides (SiCN) ceramic has been reported. [18][19][20] The dielectric measurements were carried at various temperatures (À50 to 300 C) and frequencies (10 À2 to 10 8 Hz). The material displayed DOI: 10.1002/pssa.202000417…”

“…[ 24,26–28 ] Recently, low‐frequency (<10 MHz) dielectric behavior of precursor‐derived amorphous nonoxide silicon carbonitrides (SiCN) ceramic has been reported. [ 18–20 ] The dielectric measurements were carried at various temperatures (−50 to 300 °C) and frequencies (10 −2 to 10 8 Hz). The material displayed ε ′ > 10 5 , which is higher than the commonly used ferroelectric and antiferroelectric materials (Figure 1b); however, their tan δ values are much higher, resulting from DC conduction and interfacial charges.…”

“…a) Number of publications on CP in the year 2000–2020 (database from Web of Science) and b) Ragone chart showing the categorization of dielectric materials based on dielectric permittivity ( ε ′) and dielectric loss (tan δ ) (reproduced from refs. [5‐20]).…”