Perovskite formation sequence by B-site precursor method and dielectric properties of PFW-PFN ceramics

The reaction sequences of B-site precursors and perovskite phase formation, crystallographic data, dielectric properties, and microstructures in the PFW-PFN system are reported. The formations of B-site precursors and perovskite phases were studied by X-ray diffraction. B-site precursors formed directly from the constituent oxides or through a competition with a pyrochlore-type structure, while perovskite phases were developed through a competition with pyrochlores. Maximum dielectric constants and Curie temperatures (@ 100 kHz) of PFW and PFN were found as 8,400 and 23,000 at -71 degrees and 110 degrees C, respectively. PFN exhibited a typical relaxer behavior, whereas PFN showed little relaxation.