Abstract:A correlation between structure and vibrational properties related to a ferroelectric to paraelectric phase transition in perovskite Pb (1-x) (Na 0.5 Sm 0.5 ) x TiO 3 (0≤x≤0.5) (PNST-x) polycrystalline powders is discussed. Substitution leads to reduction of tetragonality which is associated with a shift of the phase transition to lower temperatures. The nature of the phase transition gets diffused with increasing substitution.Keywords: Structural properties, Raman spectroscopy, Dielectric, Phase transition.
IntroductionPbTiO 3 is known to be a strong ferroelectric perovskite compound. A structural phase transition from tetragonal (P4mm) to cubic (Pm3m) phase at 763K is observed in PbTiO 3 . Tetragonality, measured by c/a ratio is frequently related to ferroelectric properties. For PbTiO 3 , c/a ratio is ~1.06 at room temperature [1][2][3][4][5]. Properly substituted PbTiO 3 has different applications as capacitors, nonvolatile memories, ultrasonic transducers, pyroelectric infrared sensors, piezoelectric actuators due to their highly anisotropic nature of elastic, piezoelectric, and electro-optic properties etc. [6][7][8].Physical properties and device applications of ferroelectric perovskite (ABO 3 ) compounds like PbTiO 3 and BaTiO 3 have been studied extensively due to their technological importance. Based on the fact that PbTiO 3 is toxic and volatile in nature and not environmental friendly many reduced lead content ferroelectric materials has been investigated, such as