Large electromechanical strain in lead-free binary system K0.5 Bi0.5 TiO3- Bi (Mg0.5 Ti0.5) O 3

Solid solution formation in the lead-free binary system (1-x)K 0.5Bi0.5TiO3-xBi(Mg0.5Ti 0.5)O3 has been studied for compositions x ≤ 0.12. X-ray powder diffraction shows single-phase perovskite for x < 0.1, and a mixed phase region between tetragonal and pseudocubic phases for compositions 0.04 ≤ x ≤ 0.06. Large electromechanical strains of ∼0.3% at fields of 50 kV/cm are recorded in the mixed phase region, with d33* (Smax/Emax) values of ∼600 pm/V. The materials sustain polarization at low electric fields with remnant polarization ∼18 μC/cm2 and coercive field ∼20 kV/cm for x = 0.06. Relative permittivity-temperature plots display relaxor characteristics, with peak temperature ∼340°C.