Evidence of nuclear quadrupole interaction in BaTi0.7Sn0.3O3 relaxor around dielectric maxima: A synchrotron-based <mml:…

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The present work reports the ferroelectric (FE) element/site specific spectroscopic measurements in BaTi0.7¹¹⁹Sn0.3O₃ relaxor using ¹¹⁹Sn hyperfine interaction studies. The relaxor properties in the studied sample are confirmed from the macroscopic measurements such as temperature dependent dielectric constant measurements. The presence of quadrupole splitting (QS) below its dielectric maxima (Tₘ) is confirmed unambiguously using synchrotron radiation perturbed angular correlation experiments. Further, temperature dependent nuclear forward scattering data clearly depict the development of QS below Tₘ. Finite values of QS with temperature, below Tₘ, unambiguously indicate the development of electric field gradient around Sn/Ti sites in BaTi0.7¹¹⁹Sn0.3O₃ relaxor, emphasizing the applicability of conventional FE models in explaining relaxor properties. The phonon density of states (PDOS) obtained from nuclear inelastic scattering measurements has been found to qualitatively match the results of PDOS calculated from molecular dynamics simulations and experimental Raman modes that are considered to be characteristic of Ti site in BaTiO₃.