Effect of Sr[formula omitted] doping on the structural, electrical and optical properties of BiFeO3

Abstract

Multiferroic nanoparticles of Bi1−xSrxFeO3 (x = 0.00, 0.05, 0.10, 0.15, 0.20) were prepared by sol–gel route and the effect of Sr2+ concentration on the structural, electrical and optical properties have been studied. The average crystallite size of bismuth ferrite calculated from XRD result was 29–50 nm and is consistent with the scanning electron microscopy (SEM). The lattice constants, unit cell volume and porosity are found to increase with the increase in x. Moreover, the dc electrical resistivity was found to decrease with the increase of temperature reflecting the semiconducting nature of the material. Remarkably, the doping of Sr2+ ions are considered to originate small polaron which grows in size with x and reflects a structural distortion at x > 0.15. Infrared reflectivity (30–1000 cm−1) was used to study the phonon contribution to the intrinsic structural response of the system. Interestingly structural distortion is evident for x > 0.15 as observed through high frequency phonon shifts .