Role of A-site Ca and B-site Zr substitution in BaTiO3 lead-free compounds: Combined experimental and first principles density functional theoretical studies

We report on the combined experimental and theoretical simulation results of lead-free ferroelectrics, Ba(1-x)CaxTiO3 (x = 0.0–0.3) and BaTi(1-y)ZryO3 (y = 0.0–0.2), synthesized by standard solid state reaction method. First principles density functional calculations are used to investigate the electronic structure, dynamical charges, and spontaneous polarization of these compounds. In addition, the structural, ferroelectric, piezoelectric, and dielectric properties are studied using extensive experiments. The X-ray diffraction and temperature dependent Raman spectroscopy studies indicate that the calcium (Ca) substituted compositions exhibit a single phase crystal structure, while zirconium (Zr) substituted compositions are biphasic. The scanning electron micrographs reveal the uniform and highly dense microstructure. The presence of polarization-electric field and strain-electric field hysteresis loops confirms the ferroelectric and piezoelectric nature of all the compositions. Our results demonstrate h...