Phase Transitions in PbTi(x)Hf(1-x)O3 Determined by Thermal Analysis and Impedance Spectroscopy

R.E. ALONSO; M.A. DE LA RUBIA; J. DE FRUTOS; A. LOPEZ GARCIA

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY

SPRINGER

Año: 2009 vol. 98 p. 793 - 799

1388-6150

The objective of this study is to determine the influence of partial substitutions of Ti4+ by isovalent Hf4+ in the perovskite-type crystalline structure of PbTiO3. Different samples over the whole composition range (0£x£1) in the PbTi1-xHfxO3 family have been prepared. Phase transitions in a wide temperature range have been determined by thermal analysis (DSC) and complex impedance (IS) spectroscopy. As a consequence of  cation replacement  changes that take place in the different phase transition temperatures are reported. By both techniques, thermal analysis and electrical characterization it is shown that for all compositions prepared there is only one phase transition in a temperature range between 230 and 460ºC. With these results and the previously known, crystalline structure of PbTiO3 and PbHfO3 pure perovskites, the phase diagram of the PbTi1-xHfxO3 family is presented. A morphotropic phase transition at x~0.5 was also detected.