Azizurrahaman Ansari; Vishal Kumar Chakradhary; M. J. Akhtar
Abstract
In this article, an effort is made to synthesize the nickel ferrite nanoparticles via chemical co-precipitation method using the metal nitrates as precursors. The x-ray diffraction pattern of the as-synthesized powder sample indicates the formation of nickel ferrite with iron oxide and other impurity ...
Read More
In this article, an effort is made to synthesize the nickel ferrite nanoparticles via chemical co-precipitation method using the metal nitrates as precursors. The x-ray diffraction pattern of the as-synthesized powder sample indicates the formation of nickel ferrite with iron oxide and other impurity phases. The heat treatment of the as-synthesized powder at 600oC assists in the formation of inverse spinel phase of nickel ferrite accompanying with some fraction of iron oxide phase. The field emission scanning electron microscopy of the heat treated sample reveals the irregular particle size and shape with fine microstructures, while as-synthesized sample shows the lamina like particle morphology. The magnetization curve(M-H curve) of the heat treated sample shows the ferrimagnetic behavior with very small (negligible) values ofremanent magnetization and coercive field. Such type of magnetic characteristic indicates the signature of superparamagnetism (Mr ~ 0, Hc ~ 0) in the heat treated nickel ferrite nanoparticles with significant value of the saturation magnetization (Ms). The superparamagnetic effect in the nickel ferrite particles has great potential in the field of biomedicine for certain applications such as the effective drug delivery, and for enhancing the contrast in case of magnetic resonance imaging. Copyright © 2016 VBRI Press.
Vishal K. Chakradhary; Azizurrahaman Ansari; M.J. Akhtar
Abstract
Material synthesis is a scientific art, considering all parameters and conditions in practical view and applying them in an experiment. Properties of synthesized material can be tuned further by technically playing with concerned parameters individually. In this work, a one to one relation between the ...
Read More
Material synthesis is a scientific art, considering all parameters and conditions in practical view and applying them in an experiment. Properties of synthesized material can be tuned further by technically playing with concerned parameters individually. In this work, a one to one relation between the formation of cubic spinel ferrite structure with stable phase and morphology has been established, and corresponding changes in the magnetic properties are investigated with temperature. Heat treatment method is adopted for the preparation of nanoparticles of cobalt doped nickel ferrite Ni1-xCoxFe2O4 (x=0.5) and characterized by XRD, FESEM, TGA and VSM. Initially, as synthesized powder sample shows amorphous and weak ferromagnetic nature (Ms = 0.04 emu/g, Hc = 92.42 Oe), but heat treatment at 400ºC exhibits signature of phase formation with irregular particle shape and ferromagnetic (Ms = 6.62emu/g, Hc = 460 Oe) behaviour. On further heating upto 600ºC, the nanoparticles of Ni1-xCoxFe2O4 (x=0.5) is formed with stable cubic spinel crystal structure (lattice constant a=8.35452Å) and enhanced magnetic properties (Ms=8.24emu/g, Hc=1955Oe). Due to higher coercivity obtained of Ni1-xCoxFe2O4 (x=0.5) nanoparticles, it may be useful material in the production of data storage devices, permanent magnet, parts of electronic circuits and also in stealth technology.