PhD, 1996, University of Missouri, Rolla
Office: MN 226
Laboratory: MN 120
- Exchange Spring Magnetic Materials
- Rare-Earth intermetallics
- Core-Shell oxide nanostructured materials
- Exchange Coupled Magnetic Nanocomposites
Detailed Research Information
- 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 Ms, high
Tc and Hc, 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
- 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.