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Low‐frequency dielectric dispersion in polymer‐derived amorphous silicon carbonitride ceramics
Author(s) -
Ma Baisheng,
Cao Yejie,
Zhu Yan,
Li Xuqin,
Cheng Zhongyang
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16221
Subject(s) - dielectric , materials science , amorphous solid , relaxation (psychology) , polarization (electrochemistry) , amorphous silicon , ceramic , microstructure , silicon , polaron , polymer , composite material , condensed matter physics , dielectric loss , dispersion (optics) , conductivity , electron , optics , optoelectronics , crystalline silicon , crystallography , chemistry , physics , psychology , social psychology , quantum mechanics
The dielectric response of polymer‐derived amorphous silicon carbonitride ( PDC ‐Si CN ) material was studied over a wide frequency range from 1 mH z to 10 MH z. Aside from presenting a relaxation process over 10 5 to 0.03 Hz frequency range, the material showed a strong low‐frequency dielectric dispersion ( LFDD ), which resulted in extremely high permittivities (up to 10 5 ) at frequencies lower than 0.03 Hz. It is identified that this LFDD resulted from relaxation process was not induced by conductivity. Therefore, PDC ‐Si CN material showed two relaxation processes. Based on its microstructure, two polarization mechanisms were proposed for PDC ‐Si CN : 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 SiC x N 4− 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.