Structural, dielectric, ferroelectric and optical properties of Er doped BiFeO3 nanoparticles

Abstract

In this work, an effort has been made to show the effect of Er doping on the dielectric, electrical, ferroelectric, and optical properties of BiFeO3 (BFO) nanoparticles prepared by the sol-gel route. XRD of Bi1-xErxFeO3 samples revealed that the rhombohedral (R3c) structure is stable for 0 ≤ x ≤ 0.08 with distortional changes, whereas a co-existence of two phases, rhombohedral (R3c) and orthorhombic (Pn21a) is present for x = 0.12. At room temperature, dielectric properties are slightly improved with the appearance of defects at a higher temperature. The ln σacvs. 1000/T plots revealed the presence of different Arrhenius-type thermally activated mechanisms and, for their analysis, were divided in five regions: the low temperature regions (I and II), followed by a small polaron hopping (intermediate region III) and a single and a double oxygen vacancies regions in the high temperature side (IV and V). Er doped BFO displays an improvement of the dielectric properties with respect to those of BFO, clearly reflected in better P-E loops. UV–Vis spectroscopy revealed the optical band energy lies in the 2.10 eV–1.70 eV interval, suggesting possible applications in the visible range of the spectrum. The multiferroic properties at room temperature make it a good candidate for future potential application in memory devices.