Soft Mode in Heteroepitaxial (Ba, Sr)TiO3MgO Thin Films

Abstract

Polarized Raman spectra of tetragonally distorted (Ba1—xSrx)TiO3/MgO ferroelectric films were obtained in special scattering geometries using a micro-Raman set-up. The underdamped E(TO) soft mode was unambiguously observed in the films with x = 0.30 and 0.45. The low-temperature behaviour of the E(TO) soft mode for x = 0.45 was found substantially different from those observed in pure crystals and bulk solid solutions.