Electric field dependence of characteristic temperatures in PbSc0.5Ta0.5O3 and Pb0.78Ba0.22Sc0.5Ta0.5O3 relaxors studied via acoustic emission
Department of Applied Physics, The Hebrew University of Jerusalem - Jerusalem 91904, Israel
2 Department Geowissenschaften, Universität Hamburg - Grindelallee 48, D-20146 Hamburg, Germany, EU
3 Institute of Solid State Physics, Bulgarian Academy of Sciences - Boulevard Tzarigradsko Chausse 72, 1784 Sofia, Bulgaria, EU
Accepted: 14 April 2011
Two model relaxor ferroelectrics PbSc0.5Ta0.5O3 (undergoing a spontaneous para-to-ferroelectric phase transformation) and Pb0.78Ba0.22Sc0.5Ta0.5O3 (no long-range ferroelectric order in the absence of an external electric field) were studied by acoustic emission in the temperature range 200–600 K under a dc field E. Both compounds exhibit a para-to-antiferroelectric transformation at Tn, which is slightly above the temperature of the dielectric-permittivity maximum. For both compounds the intermediate temperature T* increases linearly with increasing E. The dT*/dE slope is larger than that of the ferroelectric transformation temperature Tc, similar to the transformation phenomena in BaTiO3. The T*(E) increase is suggested to be due to enhanced dipole polarizations inside the polar nanoregions.
PACS: 77.80.Jk – Relaxor ferroelectrics / 77.80.B- – Phase transitions and Curie point / 43.40.Le – Techniques for nondestructive evaluation and monitoring, acoustic emission
© EPLA, 2011