Effect of La substitution on phase transitions in lead zirconate stannate titanate (55∕35∕10) ceramics

Investigations of the structure-property relationships in Pb1−3x∕2Lax(Zr0.55Sn0.35Ti0.10)O3. (PLZST100x∕55∕35∕10) have been performed for x between 0 and 0.08 by means of x-ray diffraction, electron microscopy, polarization, and dielectric studies. Factors affecting the phase stability were determined. The base composition PLZST0∕55∕35∕10 was ferroelectric (FE) at room temperature and transformed into an incommensurate antiferroelectric (AFEin) state on heating. Evidence was presented that low La addition could destabilize the FE state and PLZST2∕55∕35∕10 became AFEin at room temperature, which transformed to a multicell cubic state and then to a paraelectric (PE) phase upon heating. Further increase of La content enhanced the stability of the AFEin state at room temperature. Moreover, addition of La could also broaden the AFEin-PE phase transition temperature region and decrease its maximal dielectric constant εmax′.