Large strain in Bi0.5(Na0.78K0.22)0.5TiO3-Bi(Mg0.5Ti0.5)O3 based composite ceramics under low driving field

The fabricated relaxor/ferroelectric composite showed relaxor and/or ferroelectric phase depending upon the weight content of added Bi0.5Na0.5TiO3 (BNT) seeds. Bi0.5Na4.5Ti4O15 large particles were processed as precursors and modified to BNT plate-like particles by means of a double molten salt method. The base material 0.96Bi0.5(Na0.78K0.22)0.5TiO3-0.04Bi(Mg0.5Ti0.5)O3 (BNKT-0.04BMT) was synthesized by means of a solid state reaction technique. The 0-3 type composite of BNKT-0.04BMT powder and BNT seeds was chosen because of the compatibility between their perovskite structures. BNT perovskite seeds were added in 10, 15 and 20 wt% proportions to the base BNKT-0.04BMT matrix powder. The highest content of added BNT seeds (20 wt%) yielded BNKT-0.04BMT that showed ferroelectric behavior. A large electric field-induced normalized strain (Smax/Emax = 560 pm/V) was witnessed at the low driving field of 2.5 kV/mm for the composition with 15 wt% BNT seeds.