Tunning of rheological and magnetic properties of Ni doped magnetite based magnetic nanofluid

The effect of nickel doping on the structural and magneto-rheological properties of Fe3O4 based nanomagnetic fluids (NMFs) having the composition NixFe3-xO4 (0 <= x <= 0.8) has been studied. The structural and compositional analysis confirmed the nanoscale regime (similar to 10 nm) of samples prepared by chemical co-precipitation method and structural analysis was performed by XRD pattern to ascertain the effect of Ni doping. From the UV-Visible spectroscopy studies, the energy band gap was found to be in the range 2.2-3.0 eV with increase in Ni concentration. The magnetic measurements reveal the lower values of coercivity and remanence. The magnetorheological measurements confirm that in all samples shows a non-Newtonian shear thinning behavior and the increase of viscosity and dipolar interactions while increasing the magnetic field. Whereas in absence of field, higher grain boundaries enhance the interlayer friction and higher viscosity with Ni doping.

Automated summary

The effect of nickel doping on the structural and magneto-rheological properties of Fe3O4 based nanomagnetic fluids has been investigated. The results show that nickel doping can increase the nanoscale regime of the samples, enlarge the energy band gap, and decrease the coercivity and remanence. In addition, the viscosity and dipolar interactions can be enhanced with nickel doping in the presence of a magnetic field.