Enhancement of the magnetic and optical properties of Ni0.5Zn0.5Fe2O4 nanoparticles by ruthenium doping

The characterization of Nanosized Ni0.5Zn0.5RuxFe2-xO4 (0.00 <= x <= 0.015), prepared by the wet chemical coprecipitation method, is reported in the current investigation. X-ray powder diffraction (XRD) analysis has confirmed the formation of a single phased spinel cubic structure. While transmission electron microscopy (TEM) studies have shown an increase in the particle size for high content of Ru3+ doping. The elemental composition of all samples was investigated using energy dispersive x-ray (EDX) measurements. The results showed a reciprocal relation between the Fe3+ and Ru3+ contents, suggesting the successful substitution of Ru(3+)in Fe3+ sites. UV-Vis spectroscopy studies, via Urbach energy analysis, proposed a perturbation in the band structure of Ni0.5Zn0.5Fe2O4 induced by Ru3+ substitution, affecting both the direct and indirect bandgap energies. Excitation wavelength-dependent photoluminescence (PL) studies, presented for the first time, have shown a strong dependence of the emission spectra on both the excitation wavelength and Ru3+ doping. The PL analysis suggests the utilization of Ni0.5Zn0.5RuxFe2-xO4 as a candidate for photocatalytic applications. Furthermore, VSM studies, have shown a transition from superparamagnetic to soft ferromagnetic for Ru3+ doped samples. The saturation magnetization, coercivity, and effective anisotropy were enhanced as a result of Ru3+ doping. Finally, photocatalysis experiments have shown an enhancement of the degradation rate of nitrobenzene for the sample with x = 0.0125 with the ability of magnetic recycling, in agreement with the PL and VSM studies.