Electrical properties and defect compensation mechanism of B-site Cu~(2+) substituted K_(0.5)Na_(0.5)NbO_3 ceramics

摘要

Cu2+ substituted K0.5Na0.5NbO3 ceramics at B-site K0.5Na0.5(Nb1-xCux)O3-3x/2 (KNNC) were prepared by a solid state method. The dielectric, ferroelectric properties and defect compensation mechanism were studied. With the concentration of Cu2+ increasing from 0.005 to 0.10, permittivity and dielectric loss decrease, but further increasing the concentration of Cu2+ increasing leads to the increment of permittivity and dielectric loss. All KNNC ceramics exhibit double hysteresis loop characteristics. When the doping concentration Cu2+ is low (x = 0.0075), the double hysteresis loop disappears at large electric field, nonetheless, when x = 0.015, it maintains the characteristics of the double hysteresis loop even under the high electric field. The corresponding mechanism is explained from the aspects of correlation between defect dipoles and polarization orientation.