High electric-field-induced strain of Pb(Mg1/3Nb2/3)O3–PbTiO3 crystals in multilayer actuators

An optimum composition range (29%≤x≤31%) of 〈001〉 oriented (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMNT) crystals was ascertained for multilayer actuator applications, which exhibited high-strain and low-hysteresis behavior. A −1.5 kV/cm negative E-field can be applied to PMNT ferroelectric samples with low hysteresis. Forty layer actuators with individual element sizes of 7×7×0.7 mm3 were fabricated under identical processing conditions using two different materials: (1) single crystal PMNT and (2) commercial PZT-SF ceramics. Under free-load conditions, 48 μm displacements can been achieved in PMNT actuators at electric fields ranging from −1.5 to 10 kV/cm, which is more than twice the displacement of the PZT-SF actuators driven from −10 to 10 kV/cm. Under 4 kg loading, the displacements in PMNT stain actuators are decreased to 42.5 μm.