Role of phonon mode in the enhancement of ferroelectric polarization in a perovskite-based eco-friendly functional material

Abstract We report here the role of component freezing of three-dimensional polar ( ) phonon mode corresponding to the center of cubic Brillouin zone in tuning the structure-property correlations of a scientifically enriched and technologically important barium-titanate–based eco-friendly functional material (Ba 0.92 Ca 0.08 )(Zr 0.05 Ti 0.95− x Sn x )O 3 ; BCZTSn x synthesized via solid-state reaction method. The combined X-ray diffraction, Raman spectroscopic analysis, and temperature-dependent dielectric studies have revealed the presence of several crystallographic phase transitions with coexisting phases, viz., , as a function of Sn( x ) content. These crystallographic phases, viz., P 4 mm , Amm 2, and R 3 m results due to freezing of the component(s) of phonon mode (belonging to space group), with the respective order parameter directions (0,0, a ), ( a , a ,0), and ( a , a , a ) leading to ferroelectric polarization along , and directions, respectively. The ceramic composition corresponding to exhibits a significant reduction in the coercive field ( E c ) and an enhancement in ferroelectric polarization ( P r ) in comparison to , inferred from PE loop measurements. The enhancement in ferroelectric polarization at has been attributed to the inter-ferroelectric three-phase coexistence around this composition and significantly enhanced amplitudes of ferroelectric phonon modes corresponding to orthorhombic and rhombohedral phases, calculated using the symmetry mode analysis technique. The existence of a high ferroelectric polarization and low coercive field may lead to composition as an eco-friendly candidate for ferroelectric memory devices.