Piezoelectric properties of lithium modified silver niobate perovskite single crystals

We report the growth and the piezoelectric properties of lead-free perovskite single crystals of Ag1−xLixNbO3. It possesses a rhombohedral structure with high ferroelectric phase transition (Tc=548K for x=0.086) and large spontaneous polarization (Ps∼40μC∕cm2 for x=0.062) along the ⟨111⟩c direction of pseudocubic perovskite structure for x>0.05–0.06. High quasistatic d33∼210pC∕N and low dielectric constant have lead to a very large value of piezoelectric voltage constant g33∼53.9×10−3Vm∕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 perovskite structure. Our findings may stimulate further interests in the development of lead-free piezoelectrics.