Enhanced magnetic properties of Zn doped Fe3O4 nano hollow spheres for better bio-medical applications

We synthesized ZnxFe3-xO4 (x= 0.0, 0.1, 0.2, 0.3, 0.4, 1.0) nano-hollow spheres (NHSs), a promising functional magnetic material for bio-medical applications. Detailed temperature dependent magnetic studies indicate an increase in saturation magnetization (MS) with Zn doping, attaining a maximum at x= 0.2 (MS = 92.52 emu/g at room temperature), due to the replacement of antiferromagnetically coupled Fe-A(3+) ion on the A site by Zn2+ and transformation of Fe-B(2+) to Fe-B(3+) on B site for maintaining the charge neutrality. The dynamic magnetic properties of the powdered ZnxFe3-xO4 samples were investigated using frequency dependent real and imaginary parts of ac susceptibility. The data obtained by fitting Vogel Fulcher law indicates reduced dipolar interaction in our systems due to Zn doping. Applications of Fe3O4 nanostructures can be improved by doping Zn and making hollow spheres.