High-strain piezoelectric ceramics and applications to actuators

PZT-based solid solutions are very attractive piezoelectric ceramics, because they exhibit excellent piezoelectric properties such as large piezoelectric constant. In this paper we describe the relationship between piezoelectric properties and compositions, and sintering behavior of PbNiNbTiO3–PbTiO3–PbZrO3 (PNN–PT–PZ) ceramics and applications to the microactuators for magnetic disk drives. The MPB composition was determined by the temperature dependence of the relative permittivity and XRD patterns. The large piezoelectric constant (d33 = 1100 pm/V) was obtained at the MPB composition. Unique rotating symmetrical microactuators using PNN–PT–PZ ceramics show both wide stroke and high-resonant frequency. In this paper we also describe the applications of piezoelectric ceramics to tunable superconductive filters for future wireless communication systems. Low-temperature piezoelectric properties of PZT-based ceramics and frequency tunable mechanisms will be discussed. This work was supported in part by the Ministry of Internal Affairs and Communications (MIC) of Japan.