Piezoelectric properties of lithium modified silver niobate perovskite single crystals

Abstract

We report the growth and the piezoelectric properties of lead-free perovskitesingle crystals of Ag 1 − x Li x Nb O 3 . It possesses a rhombohedral structure with high ferroelectric phase transition ( T c = 548 K for x = 0.086 ) and large spontaneous polarization ( P s ∼ 40 μ C ∕ cm 2 for x = 0.062 ) along the ⟨ 111 ⟩ c direction of pseudocubic perovskitestructure for x > 0.05 – 0.06 . High quasistatic d 33 ∼ 210 pC ∕ N and low dielectric constant have lead to a very large value of piezoelectric voltage constant g 33 ∼ 53.9 × 10 − 3 Vm ∕ N for the ⟨ 001 ⟩ c -cut crystal of this simple perovskite. It has been shown that Li substitution might enhance the piezoelectric coefficient of the crystal. The excellent piezo-/ferroelectricity of this system are considered to be facilitated by the strong polarization nature of both Ag and Li in the perovskitestructure. Our findings may stimulate further interests in the development of lead-free piezoelectrics.