Phase transitions in PbZrxHf1-xO3 determined by thermal analysis and impedance spectroscopy

The objective of this study is to determine the influence of partial substitutions of Zr by Hf in the perovskite-type crystalline structure of PbZrO₃. Different samples over the whole composition range (0 les x les 1) in the PbZr_xHf_1-xO₃ family have been prepared. Phase transitions have been determined by thermal analysis (DSC) and complex impedance (IS) spectroscopy over a wide temperature range. As a consequence of the cation replacement, the changes that take place in the different phase transitions temperatures are reported. By both techniques, thermal analysis and electrical characterization, it is shown that for all compositions prepared there are 2 phase transitions in a temperature range between 160 and 230degC. With these results and the previously known crystalline structure of pure PbZrO₃ and PbHfO₃ perovskites, the phase diagram of the PbZr_xHf_1-xO₃ family is presented for the first time.