Study of enhanced magnetism in Lu doped multiferroic bismuth ferrite

Highlights: • Magnetic enhancement is observed in Lu doped BiFeO₃. • X-ray diffraction reveals strong signature for rare earth garnets. • The transition corresponding to the garnet phase is seen in M–T curve. • Secondary phase segregation in Lu doped BiFeO₃ is due to structural instability. • Garnet phase is the reason for magnetic enhancement in rare earth doped BiFeO₃. - Abstract: In this work, the enhancement in magnetic moment in Lu doped BiFeO₃ is reported. Sol–gel synthesized Bi_1−xLu_xFeO₃ (x = 0, 0.02, 0.04 and 0.05) were characterized for their phase, magnetic properties, thermal analysis and Raman scattering studies. The X-ray diffraction study revealed the segregation of rare earth garnet as secondary phase. The presence of garnet phase was reiterated in the magnetization measurements with Curie temperature at 575 K. The DSC and the Raman spectrum once again ascertain the garnet phase in the compound. We believe that the instability in the structure with lower dopant ionic radii resulted in increase in segregation of garnet and hence enhanced the magnetic moment in rare earth doped BiFeO₃ samples. We suggest that the increase in magnetic moment with decrease in rare earth dopant ionic radii reported in the literature could have a strong correlation with the structural instability and the related secondary phase segregation