Observation of dielectric anomalies and enhanced multiferroic properties in (1-x) Ba0.80Sr0.20TiO3-(x) LaFeO3 ceramics near at MPB region

Abstract

Polycrystalline solid solution of (1-x)Ba0.8Sr0.2TiO3 - xLaFeO3 (0 ≤ x ≤ 0.50) samples were prepared by a conventional solid state process. The crystal structure of the samples transformed from tetragonal structure with P4mm space group (for x < 0.15) to orthorhombic structure with Pbnm space group (x > 0.35) alongside Morphotropic phase boundary region of 0.2 ≤x ≤ 0.35 samples. The evolution in Raman modes also indicated structural phase transition of the samples and corroborated the XRD findings. An increase in grain size with increase of LaFeO3 concentration up to x = 0.30 was observed. The ferroelectric properties were strongly dependent on composition and were correlated to the crystal structure of the samples. An enhancement in magnetization along with weak ferromagnetic hysteresis loops could be the presence of long range superexchange interaction via Fe3+−O−Ti−O−Fe3+ along the pathway. Dielectric anomalies near magnetic transitions were observed for the samples with x = 0.25 and 0.35 at temperatures 293 °C and 318 °C respectively, were ascribed to presence of strong magnetoelectric coupling. The observed dielectric relaxation in loss data attributed to hopping of oxygen vacancies.