Correlation between site preference and magnetic characteristics of self assembled strontium ferrite dot array on functionalized multi-walled carbon nanotubes.

In this research work, ferrite nanoparticles with composition of SrFe12-x(Ni0.5Co0.5Ti)x/2O19 (x = 0-2.5 in a step of 0.5) were synthesized by a reverse micelle. Multiwalled carbon nanotubes (MWCNT) were also functionalized by employing poly(acrylic acid). Then the ferrite nanoparticles were deposited on the functionalized surface of carbon nanotubes by hetero-coagulation process. The volume percentage of carbon nanotubes was kept constant at 8 vol. % for synthesizing nanocomposites. The site preference of substituted cations in ferrite crystal structure was determined by 57Fe Mössbauer spectroscopy. It was proved that the substituted cations were distributed in 12 k crystallographic sites. The morphology of ferrite dot array on carbon nanotubes was studied by field emission scanning electron microscopy (FESEM). Quantum Device MPMS-5S SQUID magnetometer was used to probe the variation of magnetization with applied magnetic field. It was found that with an increase in substitution content, the saturation of magnetization and coercivity decrease. [ABSTRACT FROM AUTHOR]