Substitution-driven Structural and Magnetic Transformation of Mn- and Co-doped BiFeO3

Mn- and Co-doped and pure BiFeO3 (BFO) nanoparticles were synthesized through sol-gel method. The result of the Rietveld refinement based on X-ray diffraction (XRD) data revealed that BFO and 10 % Co-doped BFO sample crystallize in rhombohedral symmetry (R3c) structure. The transition of crystal structure can be found when Fe atoms were replaced by Mn atoms partially (from R3c to P4/mbm). Besides, Raman spectra further confirm the structure transformation which is consistent with the results of Rietveld refinements. Analysis of vibrating sample magnetometer (SQUID–VSM) magnetic hysteresis data shows the enhancement of magnetism in Mn- and Co-doped samples which were explained by the changing of bond length and angle which were obtained from the Rietveld refinement.