Anomalous piezo-dielectricity of a polymer-derived amorphous silicoaluminum oxycarbide (SiAlCO)

The piezo-dielectricity of a polymer-derived amorphous silicoaluminum oxycarbide (a-SiAlCO) was studied. The material showed a relatively high dielectric constant and anomalous piezo-dielectricity characterized by a positive pressure coefficient as high as 0.10-0.25 MPa−1. Further analyses indicated that this anomalous piezo-dielectricity resulted from an increase of polarizability with pressure. This phenomenon was ascribed to the unique self-formed bi-phasic (i.e., low-conductive ceramic and high-conductive free-carbon phases) structure of the SiAlCO material. The huge piezo-dielectric coefficient makes this material a very promising candidate for high-temperature sensing applications.