Investigation of Magnetic Behaviour of Mechanical Activation Derived Multiferroic BiFeO3

Abstract

AbstractHere we report on the synthesis of multiferroic BiFeO3 ceramics by mechanical activation and detailed investigation into its magnetic behavior. The mechanically milled ceramic was calcined at temperatures up to 800°C. X-ray diffraction studies show only the pure BiFeO3 phase forms at 700°C. Vibrating sample magnetometer (VSM) measurements were carried out up to 1.5 Tesla and the results show a weak magnetic ordering in the ceramics. The magnetic measurements were also done on the samples heat treated under various cooling conditions. VSM measurements showed pronounced effect of cooling on the Magnetization vs Field curves. Mössbauer measurements show that short range Fe2O3 ordering is still present in the sample that goes undetected by XRD. This component decreases as the calcination temperature is increased. The nature of magnetic ordering improves upon heating from 600 to 700°C, also suggested by pure BiFeO3 phase formation at 700°C. Magnetization vs Temperature measurements conducted on the sample heat treated at 700°C for 1hr followed by cooling in air show an antiferromagnetic transition at ∼370°C.