High dielectric constant polymer ceramic composites

A new polymer-ceramic composite, using the newly developed relaxor ferroelectric polymer that has a high room temperature dielectric constant as the matrix, is reported. Different kinds of ceramic powders were studied and homogeneous composite thin films (20μm) were fabricated. It was observed that the increase of the dielectric constant of the composites with the ceramic content could be described quite well by the expression developed by Yamada et al., when the ceramic content is below 60% by volume. The experimental data shows that the relative dielectric constant of composites using PMN-PT powders can reach more than 250 with weak temperature dependence (i.e., the dielectric constant changes little in a broad temperature range). In addition to high permittivity, the composite prepared in clean environment also has high breakdown field strength (120MV/m), which yields an energy storage density more than 14J/cm³. The dielectric behavior of the composite at various frequencies was also studied and the results show that the material is promising for high frequency applications.