Electric-field-induced strain mechanisms in lead-free 94%(Bi1/2Na1/2)TiO3-6%BaTiO3

Abstract

High resolution neutron diffraction has been used to investigate the structural origin of the large electric-field-induced remanent strain in 94(Bi1/2Na1/2)TiO3-6BaTiO(3) ceramics. The virgin material was found to be a mixture of near-cubic phases with slight tetragonal and rhombohedral distortions of a(0)a(0)c(+) and a(-)a(-)a(-) octahedral tilt type, respectively. Application of an electric field of 4.57 kV/mm transformed the sample to a predominantly rhombohedral a(-)a(-)a(-) modification with a significantly higher degree of structural distortion and a pronounced preferred orientation of the c-axis along the field direction. These electric field-induced structural effects contribute significantly to the macroscopic strain and polarization of this system.