Cerium induced larger lattice distortion and piezoelectric properties of Aurivillius oxide Na0.25K0.25Bi2.5Nb2O9

Bismuth layer-structured ferroelectric ceramics, K0.25Na0.25Bi2.5Nb2O9 (KNBN) with the cerium addition, were synthesized by using a solid-state reaction process. It is desirable that spontaneous polarization in the a b plane and resistivity of the KNBN ceramic could be improved by means of bismuth cation vacancies compensated by the cerium addition. Phase structure of the cerium modified KNBN ceramics were confirmed to be a two-layer Aurivillius oxide with an orthorhombic space group A2(1)am. Piezoelectric performances of the cerium modified KNBN ceramics were improved significantly compared with that of the KNBN ceramic. The maximum of piezoelectric coefficient (d(33)) was found to be 28 pC/N for the KNBN-Ce0.2 ceramic, together with high Curie temperature (T-c similar to 580 degrees C) and good temperature stability of piezoelectric properties. (C) 2018 Elsevier B.V. All rights reserved.