Studies of interface characteristics of fine-grain ferroelectric based glass-ceramic composites using impedance spectroscopy

High-quality fine-grained ferroelectric glass-ceramic composites were successfully fabricated by using a modified hybrid processing. The properties of interfaces were investigated by using impedance spectroscopy (IS). In our measured impedance spectra, a polarization with an ideal Debye behavior was observed at intermediate frequency ranging between 1 kHz and 100 kHz. This polarization was attributed to the space charge accumulation at the grain-boundary interfaces, due to the presence of large dielectric constant difference between the fillers and the host. Basing on the IS results, a brick-layer microstructural model was proposed for the ferroelectric glass-ceramic composites. Our studies indicated that the new modified hybrid processing can be used to design composites with desired interfaces that have a homogeneous dielectric constant, so as to achieve high breakdown strength, thus leading to high electrical energy density storage devices.