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)O-3. (PLZST 100x/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 PLZST 0/55/35/10 was ferroelectric (FE) at room temperature and transformed into an incommensurate antiferroelectric (AFE(in)) state on heating. Evidence was presented that low La addition could destabilize the FE state and PLZST 2/55/35/10 became AFE(in) 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 AFE(in) state at room temperature. Moreover, addition of La could also broaden the AFE(in)-PE phase transition temperature region and decrease its maximal dielectric constant epsilon(max)('). (C) 2004 American Institute of Physics.