Piezoelectric materials in the 21st century

High-quality piezoelectric single crystals, such as Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZNT) and Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMNT), have been investigated and, since their piezoelectric properties are greatly superior to those of PZT ceramics, they have been used for certain applications since the late 1990s. However, these materials have still some shortcomings, notably low Curie temperature Tc < 180 degreesC and slower growth rate, which prevent them from replacing PZT ceramics in major application field. In this paper, some possible high Tc > 200 degrees Csingle crystals are introduced. Single crystals of Pb(In1/2Nb1/2)O3-PbTiO3 (PINT) binary system and Pb(Mg1/3Nb2/3)O3- Pb(Sc1/2Nb1/2)O3PbTiO3 (PSMNT) ternary system have been synthesized and their electrical properties are reported. In addition, a novel guiding principle for discovering excellent piezoelectric materials, namely the presence of low-molecular-mass B-site ions which can enter the lead-perovskite structure.