Composition dependence of phase structure and electrical properties of (1−y)Bi1−x Nd x FeO3−y BiScO3 ceramics

Abstract

In this work, we have studied a new lead-free ceramic of (1 - y )Bi1 - x Nd x FeO3- y BiScO3 (0.05 £ x £ 0.15 and 0.05 £ y £ 0.15) prepared by a conventional solid-state method, and the influences of Nd and Sc content on their phase structure and electrical properties were investigated in detail. The ceramics with 0.05 £ x £ 0.10 and 0.05 £ y £ 0.15 belong to an R3c phase, and the rhombohedral-like and orthorhombic multiphase coexistence is established in the composition range of 0.125 £ x £ 0.15 and y =0. The electrical properties of the ceramics can be enhanced by modifying x and y values. The highest piezoelectric coefficient ( d 33~51 pC/N) is obtained in the ceramics with x =0.075 and y =0.125, which is superior to that of a pure BiFeO3 ceramic. In addition, a lowest dielectric loss (tan δ ~0.095%, f =100 kHz) is shown in the ceramics with x =0.15 and y =0 due to the involvement of low defect concentrations, and the improved thermal stability of piezoelectricity at 20–600oC is possessed in the ceramics. We believe that the ceramics can play a meaningful role in the high-temperature lead-free piezoelectric applications.