Structural and Electrical properties of La~(3+) doped BiFeO_3 Multiferroics

摘要

In the present work, BFO doped with Lanthanum has been synthesized by the Sol-Gel method. The wet chemical method is found suitable for the BFO synthesis as it is a low-temperature synthesis method and avoids evaporation of Bismuth from the BFO. The synthesized Bi_(1-x)La_xFeO_3 (x = 0.0, 0.10, 0.15, 0.20, 0.25, 0.30) samples have been characterized by X-ray diffraction for structural analysis. The electrical properties of samples have been observed by measuring the room temperature and temperature-dependent dc electrical resistivity, and activation energy. The XRD patterns reveal almost a single crystalline phase of all the samples with only a few traces of an additional phase of Bi_2Fe_4O_9. The Lanthanum doped BFO is found to have a pseudo-cubic rhombohedral perovskite-type structure having space group R3c. The grain size calculated using the Scherrer formula is 27 nm for un-doped BFO and is found La-concentration dependent. The dc resistivity measurements reveal the semiconducting behavior of samples; resistivity increases on increasing the La-concentration in BFO while decreases on increasing temperature. The La~(3+) ion which replaces Bi~(3+) in BFO stabilizes the perovskite structure by preventing Bi~(3+) loss due to volatilization and removes charge vacancies; thus improving the electrical properties of BFO.