Synthesis of high-purity nanocrystalline BiFeO3

The effects of mechanical activation energy on the solid-state synthesis process of BiFeO3

“…Similar disordered structures can also be found in the previous literature for the similar high-energy ball-milled oxide-oxide systems [9,23,24]. Mechanical activation of starting oxides resulted in the following steps: initial distortion of the crystal structure of reactants; formation, accumulation, and interaction of linear and point defects; and disintegration of the materials.…”

“…Therefore, applying the energy of 171.18kJ/g is necessary to form an amorphous structure for the present oxide-oxide system. It can be observed that bismuth oxide amorphization has occurred at the first steps of mechanical milling, while the characteristic peaks of iron oxide exist even in sample C. This can be related to the fact that the iron oxide is a harder reactant in comparison with the bismuth oxide [9].…”

“…Maurya et al [12] reported that mechanical activation of precursors lowered the BiFeO 3 phase formation temperature by about 100˚C and improved the properties of powders, compared to conventionally synthesized sample. Egorysheva et al [9] have also synthesized BiFeO 3 by mechanical activation assisted method, under different milling times and synthesis temperatures. They concluded that mild milling enhances the purity and magnetic properties of products.…”

“…The most common technique to fabricate perovskite-type structure materials such as BFO is conventional solid state route which includes the calcination of a mixture of bismuth and iron oxides [7,8]. However, materials prepared by this method, which require high temperatures and long annealing times, inevitably contain Bi 2 Fe 4 O 9 and Bi 25 FeO 40 as impurity phases, which considerably weaken the properties of the material [9]. Furthermore, conventional route has poor reproducibility and results in coarse powders [10].…”

“…MA carried out by high-energy ball milling is used to improve the reactivity of the precursors so that the desired phase is formed at a reduced calcination temperature due to the enhanced diffusion rates and the microstructural refinement [11][12][13][14]. Since increasing the calcination temperature causes the decomposition of BiFeO 3 phase to impurity phases [15,16], lowering the BFO formation temperature allows one to carry out synthesis in the region where this compound is more stable [9]. Maurya et al [12] reported that mechanical activation of precursors lowered the BiFeO 3 phase formation temperature by about 100˚C and improved the properties of powders, compared to conventionally synthesized sample.…”