Dielectric Anomaly in La_0.7Sr_0.3Fe_0.05Mn_0.95O₃/BaTiO₃Composite

Abstract

La0.7Sr0.3Fe0.05Mn0.95O3/BaTiO3 composite was synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopic (TEM), ac conductivity (σac) and dielectric measurements (ϵr). The crystal structure of this composite have been determined by the Rietveld refinement powder XRD data at room temperature which confirmed by TEM. The dielectric constant (ϵr), dielectric loss (tan δ) and ac conductivity (σac) was investigated in the frequency (0.120–100 kHz) and temperature (293–401 K) The ac conductivity and loss tangent (tan δ) measurements conclude that the conduction mechanism in this sample is due to small polaron hopping. The composite sample exhibited broad dielectric anomalies in the vicinity of the ferroelectric-to-paraelectric transition temperature. The Curie-Weiss law was found to be valid at a temperature above the transition temperature.