Macroscopic ferroelectricity and piezoelectricity in nanostructured NaNbO3 ceramics

NaNbO3 sits at an instability between its ferroelectric and antiferroelectric phases, but its nanoscale polarization behavior is rarely reported. In this work, we produced high-density NaNbO3 nanostructured ceramics with a grain size of 50 nm by spark plasma sintering of nanocrystalline powder, which was obtained by mechanosynthesis. The nanostructured ceramics exhibited a symmetrical ferroelectric loop and increased relative permittivity. We believe that the increased internal stress at the nanoscale stabilized the ferroelectric domain structure, which promoted macroscopic piezoelectricity, demonstrating its potential uses in nanoelectromechanical systems.