Synthesis and Characterization of Ni-Doped Fe₃O₄/ZnS Core-Shell Spheres

In this study, we successfully synthesized a series of Ni-doped Fe3-xO4 (
$x$
= 0, 0.014, 0.041, and 0.068) nanoparticles using the solvothermal reduction technique. Additionally, Fe3-xNixO4/Zinc sulfide (ZnS) core-shell nanocomposites were prepared via the seed-mediate growth approach. Our investigation focused on exploring the structural, morphological, optical, electrical, and magnetic properties of these nanoparticles, with a particular emphasis on tuning the ZnS shell thickness. The magnetic measurements revealed that all the samples exhibit ferromagnetic behavior, with saturation magnetization values of 15.9 and 9.8 emu/g, along with coercivities of 79.82 and 82.2 Oe for the first and second layers of Fe3-xNixO4/ZnS, respectively. Furthermore, the photoluminescence spectrum exhibited a broad blue emission from the Fe3-xNixO4/ZnS core-shell nanocomposites. Regarding electrical properties, we observed that the electrical resistivity of both Fe3-xNixO4 and Fe3-xNixO4/ZnS first and second layers increased with the shell thickness, ranging from 0.60 to 16.20 and
$591.75 \Omega $
-cm, respectively. This increase in resistivity can be attributed to the ZnS layer, which enhances the potential barrier height, impeding electron transport. Based on our findings, we conclude that the synthesized Fe2.959Ni0.041O4/ZnS core-shell nanocomposites hold great potential for electronic, magnetic, and optical applications. The ability to tune the ZnS shell thickness allows us to optimize the properties of the nanoparticles, making them suitable for a range of advanced technological applications.