Structural, dielectric and magnetic domains properties of Mn-doped BiFeO3 materials

The pure and Mn-doped BiFe1-xMnxO3 (x = 0.00, 0.02, 0.05, 0.10) nanomaterials have been prepared by coprecipitation method. The powder X-ray diffraction pattern analysis shows a structural phase transformation from rhombohedral to orthorhombic, as Mn content in the doped BiFe1-xMnxO3 increases from x = 0.00 to 0.10. The Raman spectrum analysis of BiFe1-xMnxO3 also confirms structural phase transformation. The average crystallite size was calculated using the Scherrer formula and found to decrease from 100 to 60 nm. The surface structure of interconnecting cubic grain turns into spherical grains via petal-shaped grains with increasing the Mn-doping concentration. The value of dielectric constant at the frequency of 1 MHz increases rapidly from 27.2 to 76.8 whereas the tangent loss (tan delta) increases gradually from 0.26 to 0.55 as the Mn-doping concentration increases from x = 0.00 to 0.10. It reveals the enhancement of ferroelectric behavior and suppression of the leakage current density. The drastic change in the phase image contrast of magnetic force micrographs with increasing Mn-doping concentration in BiFe1-xMnxO3 also indicates the improvement of the ferromagnetism.