Title :
Synthesis and Characterization of Co-Ni and Fe
O
-Pd Nanocomposites
Author :
Nica, Valentin ; Brinza, Florin ; Caltun, Ovidiu F. ; Hempelmann, Rolf
Author_Institution :
Fac. of Phys., Alexandru loan Cuza Univ. of Iasi, Iasi, Romania
fDate :
4/1/2012 12:00:00 AM
Abstract :
Co-Ni needle-like and Fe3O4-Pd spherical nanoparticles were prepared by water-in-oil microemulsion (W/O). The as-synthesized nanoparticles have been encapsulated by silica (SiO2) and polyvinyl alcohol (PVA) in N2 atmosphere. Their structure and magnetic properties were evaluated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The influence of structural modifications to the magnetic properties of nanocomposites has been investigated. Powder X-ray diffraction analysis indicated the formation of face-centered cubic phase for both Co-Ni and Fe3O4-Pd systems. The average crystallite size for the studied samples has been calculated in the range of 7-26 nm. TEM images revealed the morphology of the particles as needle-like nanoparticles for Co-Ni alloy and spherical for Fe3O4-Pd system. The magnetization curves of nanocomposites at room temperature demonstrated coercivity values between 8.2 and 15.5 kA/m for Co-Ni nanocomposites and superparamagnetic behavior of Fe3O4-Pd nanocomposites due to the small-size effect of nanoparticles.
Keywords :
X-ray diffraction; cobalt alloys; coercive force; iron compounds; magnetic particles; microemulsions; nanocomposites; nanofabrication; nanomagnetics; nanoparticles; nickel alloys; palladium; superparamagnetism; transmission electron microscopy; CoNi; Fe3O4-Pd; TEM image; VSM; coercivity value; crystallite size; face-centered cubic phase; magnetic properties; magnetization curve; nanocomposites; needle-like nanoparticles; particle morphology; powder X-ray diffraction; spherical nanoparticles; structural modification; superparamagnetic behavior; temperature 293 K to 298 K; transmission electron microscopy; vibrating sample magnetometer; water-in-oil microemulsion; Iron; Magnetic resonance imaging; Nanocomposites; Nanoparticles; Nickel; Silicon compounds; Coercivity; magnetic nanoparticles (MNPs); nanocomposites; water-in-oil (W/O) microemulsion;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2011.2173665