Structural, dielectric and electrical characteristics of lead-free scandium modified barium iron niobate: Ba(Fe0.5-x ScxNb0.5)O3

Abstract

Scandium (Sc) modified barium iron niobates (i.e., Ba(Fe0.5-x ScxNb0.5)O3 (x = 0.03,0.05 and 0.07) (BFSN)) were synthesized by using a standard ceramic technology (i.e., high-temperature solid-state reaction of mixed oxide route). The analysis of room temperature X-ray diffraction data shows the monoclinic phase of the materials. The dielectric and impedance parameters were measured in different temperature (250C–500 °C) and frequency (1 kHz-1 MHz) ranges. Detailed study of temperature dependent dielectric constant shows the two anomalies; one may be related to the ferroelectric to paraelectric phase transition at about 249 °C and another at about 368 °C may be due to some extrinsic effects (due to creation of oxygen vacancies for variable oxidation states). The grains and grain boundary contributions in resistive and capacitive characteristics, temperature activated polarization mechanisms are analysed. The Leakage (J ~ E) characteristics illuminate the bulk (ohms due to hopping of charge carriers and, space charge limited) conduction processes of the samples. With the increase in scandium, diffusivity decreases in BFSN compounds.