Enhanced magnetization in multiferroic BiFeO_3 through structural distortion and particle size reduction

摘要

BiFeO3 is widely known multiferroic compound with high ferroelectric polarization but low magnetization values due to antiferromagnetic ordering. We used allied strategy of particle size reduction and structural modulation to improve the magnetization. Calcium doped Bismuth Ferrite nanoparticles were synthesized by sol-gel route. The Rietveld refinement of X-Ray Diffraction patterns indicates single phase formation with distorted rhombohedral (space group R3c) structure. The average crystallite size varies from 72 nm to 27 nm. The Unit cell volume decreases with increase in Ca concentration. The structural distortion is confirmed by Raman spectra through line width broadening and shifting of phonon frequencies. X-ray photoelectron spectroscopy revealed Fe+3 oxidation state and slight shifting of Bi 4f peak indicating the substitution of Ca2+ at Bi-site. The field dependent magnetization measurements show remnant magnetization up to 0.265 emu/gm and coercivity up to 543 Oe in Ca substituted samples.