MAGNETIC BEHAVIOR OF FUNCTIONALLY MODIFIED SPINEL Ni0.4Ca0.6Fe2O4 NANOFERRITE.

Spinel nanoferrites of composition Ni_0.4Ca_0.6Fe₂O₄ have been synthesized by sol-gel method and subsequently coated with intrinsically conducting polymers such as polyaniline and polypyrrole separately, using chemical oxidative polymerization technique. The characterization of the composites has been performed by X-ray diffraction and atomic force microscopy images. The room temperature DC electrical conductivity measurements are performed in order to understand the coating effectiveness and the nature of electrical conductivity of the composites. The Mössbauer spectroscopic studies reveal that the ferrimagnetic as well as super-paramagnetic states co-exist at room temperature (300 K) for all the samples which is found in good agreement with the DC magnetization measurement results, wherein the coercivity is observed in the M-H curves for all the samples at room temperature. [ABSTRACT FROM AUTHOR]