Phase Coexistence of Temperature-Dependent Phase Transformation in Relaxor Ferroelectric Pb(Mg_1/3Nb_2/3)_1–xTi_xO₃ Single Crystal

Abstract

Coexistence of monoclinic and tetragonal domains is evidenced in a (001)-cut Pb(Mg_1/3Nb_2/3)_0.61Ti_0.39O₃ (PMNT39%) single crystal from temperature dependent observation of domain structures and dielectric permittivity. The coexistence persists until the crystal transforms into the cubic phase near 455 K. As temperature increases, the monoclinic domains progressively transform to the tetragonal phase via polarization rotations of monoclinic distortions. This causes increasing volume of the tetragonal domain matrix as temperature increases before the cubic phase takes over.

Keywords:

• PMNT
• phase coexistence
• monoclinic
• polarization rotation
• phase transformation

Acknowledgments

The authors express sincere thanks to Dr. H. Luo and H. Cao for the crystal. This work was supported by DoD EPSCoR Grant N00014–02–1–0657.