Impact of Ni and Nd/Mn ion co-doping at A/B sites on the structural, magnetic and dielectric properties of bismuth ferrite nanoceramics

Nickel/neodymium and manganese co-doped nano-crystalline bismuth ferrite powders, with chemical formulae BiFeO3, Bi0.9Ni0.1Fe0.9Mn0.1O3 (Ni/Mn-BFO) and Bi0.9Nd0.1Fe0.9Mn0.1O3 (Nd/Mn-BFO), were synthesized using the wet chemical sol-gel autocombustion technique. XRD and FTIR measurements on calcined powders revealed the production of a perovskite phase with rhombohedrally deformed structures. Particle sizes were found to be in the range of 56 to 62 nm for all synthesized samples. SEM and EDAX measurements were performed on the sintered specimens to determine their microstructural and elemental analysis. The Nd/Mn-BFO sample showed a decrease in grain size (0.63 +/- 0.04 mu m) in comparison to the Ni/Mn-BFO sample (1.26 +/- 0.04 mu m). SEM revealed that the microstructures have uniformly connected grains with distinct grain boundaries. Dielectric experiments revealed the presence of space charge polarization with respect to frequency and temperature with low dielectric losses especially in the Ni/Mn-BFO co-doped sample. Room temperature magnetic studies on the samples reveal that Nd/Mn-BFO shows substantial improvement in saturation magnetization (4.973 emu/g) comparing to Ni/Mn-BFO (2.638 emu/g) and BFO (0.2586 emu/g). This value is relatively high compared to previously reported results with Ni/Nd-Mn doping in BFO, suggesting that these co-doped materials are suitable for the fabrication of memories, magnetic based sensors, spintronic, and actuators at high frequencies.