Dielectric, ferroelectric, piezoelectric, and electrostrictive properties of K0.5Na0.5NbO3 single crystals

Abstract

The dielectric, ferroelectric, piezoelectric, and electrostrictive properties of K 0.5 Na 0.5 NbO 3 single crystals (KNN s.c.) prepared by solid-state crystal growth are reported. The dielectric constant ( ε ) , dielectric losses ( tan δ ) , remanent polarization ( P r ) , and coercive field ( E c ) for KNN s.c. in the [ 1 3 ¯ 1 ] direction at room temperature are 1015, 1%, 17 μ C / cm 2 , and 24 kV/cm, respectively. The influence of 180° domains to the linear piezoelectric response and quadratic electrostrictive response of KNN s.c. is discussed. The piezoelectric coefficient d 33 and the electrostrictive coefficient M 33 of KNN s.c. measured using atomic force microscopy at 2 Hz was 80 pm/V and 2.59 × 10 − 14 m 2 / V 2 , respectively. The extremely high M 33 value can be explained by the extrinsic strain from the domain-wall motion. The properties of the surrounding polycrystalline KNN ceramic are added for comparison.