Effects of Bi(Mg1/2Sn1/2)O-3 Modification on the Dielectric and Piezoelectric Properties of Bi-1/2(Na0.8K0.2)TiO3 Ceramics

The effect of Bi(Mg1/2Sn1/2)O-3 (BMS) modification on the crystal structure, ferroelectric and piezoelectric properties of Bi-1/2(Na0.8K0.2)(1/2)TiO3 (BNKT) ceramics has been investigated. The BMS-substitution induced a transition from a ferroelectric (FE) tetragonal to a nonpolar pseudocubic phase, leading to degradations in the remnant polarization, coercive field, and piezoelectric coefficient d(33). However, the electric-field-induced strain was significantly enhanced by the BMS substitution-induced phase transition and reached a highest value of S-max /E-max = 633 pm/V under an applied electric field of 6 kV/mm when the BMS content reached 6 mol%. The abnormal enhancement in strain was attributed to the field-induced transition of the pseudocubic symmetry to other asymmetrical structure, which was not clarified in this work.