Synthesis, characterization and ferroelectric properties of lead-free K₀.₅Na₀.₅NbO₃nanotube arrays

Abstract

Lead-free K₀.₅ Na₀.₅ NbO₃(KNN) nanotube arrays were synthesized by a sol-gel method with anodic aluminum oxide templates. The obtained KNN nanotubes exhibited a polycrystalline and monoclinic perovskite structure with diameters of ~200 nm and wall thickness of ~30–40 nm, respectively. The polarization-electric loop curve of the nanotubes array were examined showing the values of 2Pᵣ and 2E[sub c] at about 3.4 μC/cm² and 13 kV/cm, respectively, under a maximum electric field of 12.5 kV/cm. The piezoelectric characteristics of individual KNN nanotube array was also identified through piezoresponse force microscopy.