Effect of Co substitution on the magnetic properties of BiFeO3

Bismuth ferrite is doped with a dilute concentration of cobalt, BiFe1−XCoXO3BiFe1−XCoXO3; X=0, 0.01, 0.02 is prepared by sol-gel auto combustion technique. X-ray diffraction data refined via Reitveld method shows single phase and shrinkage in cell volume for Co doped BiFeO3. Various magnetic ground states viz. superparamagnetic, glassy antiferromagnetic and glassy ferrimagnetic behavior is observed for X=0, 0.01, 0.02, respectively. A first-order magnetic transition is observed in the Arrott plot data of cobalt doped BiFeO3. Possibility of thermally induced magnetic transition is also seen in the magnetization data of cobalt doped BiFeO3. A model based on the existing spinoidal cyclic arrangement of spins is proposed to explain the observed data. Finally, a very dilute concentration of Co+3Co+3 in BiFeO3 is found sufficient to tailor the magnetic properties.

► A dilute concentration of Co-doped BiFeO3 is prepared by sol-gel method which is found to be impurity free confirmed by Reitveld Method.
► A first order magnetic transition is observed in the doped samples.
► A cycloid spin model is proposed which strengthen the observed transition.