Catching the intermediate phase in PZT 99/1 single crystals

Abstract

We have investigated single crystals of PbZrO₃ substituted with 1% of Ti (PZT 99/1) by means of optical microscopy, micro-Raman scattering, second harmonic generation and dielectric spectroscopy, on heating to and cooling from its cubic phase. Our measurements confirm that these crystals undergo two phase transitions within the approximate temperature range 488–503 K, in agreement with previous findings. The lower temperature phase, T_AFE, shows much stronger thermal hysteresis – about 10 K, which undoubtedly indicates its strong first-order character. Second harmonic generation showed a marked signal between the two anomalies, implying that the intermediate phase is non-centrosymmetric. In situ Raman spectroscopy and the presence of second harmonic signal, excluded the antiferroelectric state of this phase. The intermediate phase of PZT 99/1 crystal is similar to the rhombohedral ferroelectric with the R3m (Z = 1) space group.

Keywords:

• lead zirconate
• antiferroelectric
• ferroelectric
• phase transitions
• phonons
• Raman spectroscopy

Acknowledgements

The authors would like to thank A. Kania and K. Roleder for supplying the crystals, and D. Uherová, J. Dlouhý and M. Jurek for the electron microprobe X-ray measurements.

Additional information

Funding

This work was supported by the Czech Science Foundation [grant number 13-15110S].