Exceptionally large piezoelectric strains in BiFeO-(K Bi)TiO-PbTiO ceramics

Samples of (1-x-y)BiFeO-x(KBi) TiO-yPbTiO, where x = 0.15 and y = 0.275, were produced via a conventional mixed oxide method. Ceramics were characterized using X-ray diffraction, confirming an electric-field-induced phase change from predominantly rhombohedral to mixed phase tetragonal and rhombohedral structure upon poling. There was a remnant polarization of 34 μC cm and a total strain of 0.805% at 6.5 kV mm, the highest electric-field-induced strain reported in a polycrystalline material. A d of 205 pm V was measured and Rayleigh analysis was used to quantify the extrinsic contributions.