Effect of cooling conditions on the magnetic structure of multiferroic BiFeO3 synthesized by mechanical activation
An attempt to synthesize multiferroic BiFeO3 by mechanical milling Bi2O3 and Fe2O3 powders showed very interesting results. 100 h milled powder was calcined at different temperatures and it was found that the BiFeO3 phase forms at 700°C followed by slow cooling. The magnetic behaviour and phase formation crucially depended on the cooling conditions. The samples were cooled from the calcinations temperature of 700°C in four different ways and Mössbauer measurements revealed different kinds of phases formed in these conditions. It was found that slow cooling favours BiFeO3 formation while rapid cooling leads to retention of Fe2O3. This was corroborated by differences in the magnetic ordering of phases as revealed by Mössbauer spectroscopy.
KeywordsMagnetic structure Multiferroic BiFeO3 Mechanical activation Mössbauer spectroscopy
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