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

• BiFeO3 was successfully synthesized via a mechano-thermal route.
• The effects of milling energy on the process were studied.
• Applying an optimum milling energy lowered the formation temperature of BiFeO3.
• Sample with optimum energy showed antiferromagnetic state and less leakage current.

The effects of milling energy induced during intermediate mechanical activation of precursors on the synthesis of nano-structured BiFeO3 powders have been systematically investigated. X-ray diffractometer, laser particles size analyzer, field emission scanning electron microscope, vibrating sample magnetometer and electrical evaluation techniques were used to study phase composition, particles size distribution, morphology, magnetic properties and ferroelectric properties of the products, respectively. Applying a total energy of 171.18 kJ/g during milling led to formation of an amorphous structure which resulted in decreasing the formation temperature of bismuth ferrite phase by about 100 °C, although small amounts of secondary phases were detected. This sample shows the mean particles size of 170 nm and the mean crystallite size of 40 nm, when calcined at 750 °C. Saturation magnetization (MS) increased from 0.054 to 0.071 A m2/kg and coercive field (HC) decreased from 32.63 to 6.37 kA/m by increasing the milling energy from 13.48 to 171.18 kJ/g. In addition, electrical hysteresis loops demonstrated a decrease in the current leakage by increasing the milling energy and lowering the calcination temperature.

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