NSF Funded Research

Exchange Spring Magnetic Materials: Exchange spring magnetic materials, hard-soft phase materials, are synthesized via electroless platting method. Hard magnetic nanoparticles such as SmCo5 are elecroless platted with soft magnetic layers of FeNi or FeCo. Usually the soft layer is amorphous. Furthre catalytic nitrogenation of this composite is carried out at substantially low tempearture at around 350 C to obtain FeN phase with high magnetic moment. The low tempearture nitrogenation is possible because of presence of Ni in FeNi which act as catalyst in breaking ammonia gas at low temperature.

Rare-Earth intermetallics: The study focuses on improving magnetic properties of R2Fe17 intermetallics via grain refinement either by refractory metal doping for Fe or high energy ball milling. The indept study is being structural and magnetic study is being conducted using XRD, TEM, SQUID, and Mossbauer Spectroscopy.

Core-Shell oxide nanostructured materials: Our group has developed experties in synthesis of multifunctional magnetic core-shell nanocompoeite materials for various application ranging from biomedical, solar, or magnetic. The core-shell nanocomposites are synthesize using hydrothermally derived carbon nanosphere templates.

Sr/Ba-Hexaferrites: Hexaferrites, Sr(Ba)Fe₁₂O₁₉, with magnetoplumbite structures have been widely investigated and used as permanent magnets because of their high M_s, high T_c and H_c, high environmental stability, and low price for production.The intrinsic magnetic properties of Sr-hexaferrite are found to be affected by the partial substitution for Sr or Fe sites, or both. Owning to the varied 4f electron shell, orbital and spin magnetic moments, rare-earth elements were usually selected as the substitution elements. The study focuses on various doping strategy for imporving magnetic properties of these ferrites.

Exchange Coupled Magnetic Nanocomposites: Ferromagnetic (FM)-antiferromagnetic (AFM) nanocomposites are synthesised using mechanical ball milling and hydrothermal synthesis techniques. Exchange bias properties of these composites are studied using SQUID magnetometer. Several exchange coupled nanocomposite such as FeNi-CoO, FeNi-CuO, FeNi-NiO, SmCo5-NiO etc. These exchange biased nanocomposites are synthesized using ball milling and wet-chemical techniques in our laboratory.