Structural, vibrational and magnetic properties of sol-gel derived BiFe1-xCoxO3 samples

BiFe1-xCoxO3 samples (with x = 0.0, 0.01, 0.02, and 0.05; named as BFO, BFCO-1, BFCO-2, and BFCO-5) were prepared using the sol-gel process. The impact of Co3+ substitution on the structural, vibrational, and magnetic characteristics of BiFeO3 was studied(.) The pure phase polycrystalline nature of prepared samples associated to distorted rhombohedral structure of BiFeO3 was confirmed by the x-ray diffraction studies. A thorough structural analysis was done using Rietveld refinement by considering R3c crystal symmetry to evaluate lattice parameters, crystallite size, bond angles (Fe-O-Fe), bond distances, and crystal unit cell. The FTIR spectra were analyzed in the wave number range 400-650 cm(-1) to identify metal-oxygen bonds and to estimate effective mass and bond length. Raman spectra examined in the wavenumber range 50-1500 cm(-1) exhibited 13 (4A(1) + 9E) Raman active transverse and longitudinal phonon modes along with second overtones. The Fe3+ and Fe2+ states were confirmed by x-ray photoelectron spectroscopy and the concentration of the Fe2+ state increased from 26.5% for BFO to 38.6% for BFCO-2 with the substitution of Co3+ in BFO. The magnetic measurments showed weak ferromagntic behaviour which further enhanced on increasing Co3+ concentration. The maximum magentization (M-H) value increased from 0.24 emu/g to 1.02 emu/g and remnant magnetiation (M-r) values increased from 0.001 emu/g to 0.407 emu/g.

Automated summary

BiFe1-xCoxO3 samples (with x = 0.0, 0.01, 0.02, and 0.05; named as BFO, BFCO-1, BFCO-2, and BFCO-5) were prepared using the sol-gel process. The impact of Co3+ substitution on the structural, vibrational, and magnetic characteristics of BiFeO3 was studied. The structural analysis confirmed the polycrystalline nature with a distorted rhombohedral structure. The substitution of Co3+ increased the concentration of Fe2+ state and enhanced the magnetic behavior.