Synergistic effects of Ca2+ and high-valence Nb5+ co-doping on the structural, optical and magnetic properties of BiFeO3

The structural, optical and magnetic properties of BiFeO3, BiFe0.99Nb0.01O3 Bi1−xCaxFe0.99Nb0.01O3 (BCFNO, 0 ≤ x ≤ 0.25) nanoparticles synthesized via sol–gel method are investigated. It has been found that a phase transition from the rhombohedral R3c structure (x ≤ 0.10) to ideal cubic perovskite (x = 0.25) which can be attributed Ca2+ doping. Increasing dopants results in increase oxygen vacancies. As doping amount x increase, bandgap BCFNO decreases valence band spectra indicates it’s p-type semiconductor, their favorable potential photocatalytic applications. remnant magnetization Mr reaches maximum value (0.146 emu/g about 15 times compared with pure BFO) at x = 0.10. This enhancement ascribed synergistic effect A B site ions co-doping. Higher valance Nb cause size polarons bounded impurities by Ca ions.