Effect of Mn Concentration on the Structural, Ferroelectric, Optical, and Magnetic Properties of BiFeO3 Nanoparticles

Abstract

In the present work, Bi1.05 Fe1−x Mnx O3, (x = 0, 0.01, 0.03, 0.05, 0.07, 0.10) NPs were synthesized successfully using the sol-gel technique followed by annealing at 550◦ C. The synthesized NPs were investigated for their structural, ferroelectric, optical, and magnetic properties through X-ray diffraction, P-E (polarization vs. electric field) hysteresis loops, UV-vis absorption spectroscopy, Photoluminescence (PL) spectroscopy, and DC-magnetization. The analysis of XRD patterns revealed that the crystallite sizes, lattice parameters, and strain were found to be reduced with an increase in Mn concentration. The ferroelectric properties were studied from the P-E hysteresis loops, which revealed the maximum remnant polarization obtained for Bi1.05 Fe0.95 Mn0.05 O3 NPs. The UV-vis and PL spectra revealed excellent optical properties indicating a reduction (1.91–1.36 eV) in the bandgap with an increase in Mn concentration. The magnetic properties were investigated through the magnetic field (H) dependent magnetization (M) hysteresis loops. The saturation magnetization was found to be maximum (~1.4 emu/g) for Bi1.05 Fe0.90 Mn0.10 O3 NPs. The MH hysteresis loops narrow down near H = 0 forming a wasp waist shape that is maximum for Bi1.05 Fe0.90 Mn0.10 O3 NPs and may be associated with the presence of the canted spins.