Dielectric and Raman Spectroscopic Studies of Na 0.5 Bi 0.5 TiO 3 – BaSnO 3 Ferroelectric System

A series of lead‐free perovskite solid solutions of (1 −  x ) Na 0.5 Bi 0.5 TiO 3 ( NBT )— x BaSnO 3 ( BSN ), for 0.0 ≤  x  ≤ 0.15 have been synthesized using a high‐temperature solid‐state reaction route. The phase transition behaviors are studied using dielectric and Raman spectroscopic techniques. The ferroelectric to relaxor phase transition temperature ( T FR ) and the temperature corresponding to maximum dielectric permittivity ( T m ) are estimated from the temperature‐dependent dielectric data. Dielectric studies show diffuse phase transition around ~335°C in pure NBT and this transition temperature decreases with increase in x . The disappearance of x ‐dependence of A 1 mode frequency at ~134 cm −1 for x  ≥ 0.1 is consistent with rhombohedral‐orthorhombic transition. In situ temperature dependence Raman spectroscopic studies show disappearance and discontinuous changes in the phonon mode frequencies across rhombohedral ( x  < 0.1)/orthorhombic ( x  ≥ 0.1) to tetragonal transition.