Response of iron oxide on hetero-nanostructures of soft and hard ferrites.

Core-shell nanostructures of Zinc and Cobalt ferrites synthesized by solution evaporation route are observed to perform novel magnetic response. The structural and morphological analyses of ZnFe 2 O 4− core / Fe 3 O 4− shell and CoFe 2 O 4− core / Fe 3 O 4− shell nanoparticles (NPs) are confirmed with X-ray diffractometer (XRD) and high resolution transmission electron microscopy (HRTEM). Physical properties measurement system (PPMS) investigations at room temperature reveal that the synthesized core-shell NPs (∼8 nm in diameter) are in super-paramagnetic state. The coercivity of ZnFe 2 O 4 / Fe 3 O 4 is much lower than that of CoFe 2 O 4 / Fe 3 O 4 NPs (e.g., at 5 K : H c = 0.6 kOe for ZnFe 2 O 4 / Fe 3 O 4 and H c = 18kOe for CoFe 2 O 4 / Fe 3 O 4 . Fe 3 O 4 is preferable to reduce magnetic hardness for Zinc ferrite and enhance for Cobalt Ferrite. [ABSTRACT FROM AUTHOR]