Progress in lead-based ferroelectric and antiferroelectric single crystals: composition modification, crystal growth and properties

Ferroelectric and antiferroelectric materials, with complex perovskite structures, have experienced wide interest due to their peculiar structure and properties. In this highlight, recent advances of these two types of materials are reviewed, with particular emphasis on piezoelectrics/ferroelectric and antiferroelectric single crystals, owing to their ultra-high electric properties for practical application. Relaxor ferroelectric single crystals, represented by Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) at compositions near the morphotropic phase boundary (MPB), possess a high piezoelectric constant d(33) (>2000 pC N-1) and electromechanical coupling factors k(33) (90-92%). However, a low ferroelectric phase transition temperature Tr-t, far below the Curie temperature T-c restricts its further application in a broad temperature range. Some work on the design of a new pseudo-ternary system of Pb(Mg1/3Nb2/3)O-3-PbZrO3-PbTiO3 (PMN-PZ-PT) and Pb(Mg1/3Nb2/3)O-3-Pb(Fe1/2Nb1/2)O-3-PbTiO3 (PMN-PFN-PT) have been demonstrated with emphasis on the composition modification and crystal growth. Moreover, for relaxor antiferroelectrics represented by (Pb,La)(Zr,Sn,Ti)O-3 (PLZST) it is very difficult to grow bulk and high quality single crystals because of its incongruent melting. Our recent investigations on the flux growth of PLZST single crystals, especially the flux selection, compositions optimization, and defect analysis of as-grown single crystals are also described in this highlight.