Substitution-driven structural, optical and magnetic transformation of Mn, Zn doped BiFeO3

Mn, Zn doped and pure BiFeO3 were prepared by sol–gel method. The 5% and 10% Zn-doped phase crystallites have a rhombohedral symmetry (R3c) structure. Doped with 5% Mn, BiFeO3 contains both rhombohedral (R3c) and tetragonal phase (P4mm) while 10% Mn gives a rise to tetragonal phase (P4/mbm). Raman and Fourier Transformed Infrared spectra also confirmed the structure transformation. Compared with pure BiFeO3, Mn-Zn doped samples present intense blue shift as shown in UV-Visible diffuse absorption together with the decreased direct optical band gap. The substitution of Mn ions for Fe enhances ferromagnetic properties while the Zn-doped ones show linear paramagnetism. Owing to the interactions between the ferromagnetic and antiferromagnetic microdomains, Mn and Zn co-doping results in a large remanent magnetization (Mr) of 0.045 emu/g.