Achieving room temperature ferromagnetism in ZnS nanoparticles via Eu³⁺ doping

This paper reports the structural as well as the magnetic properties of ZnS:Eu³⁺ (0, 1, 2, 3, and 4 at%) nanoparticles prepared by a hydrothermal method. The compositional, structural and magnetic properties of ZnS:Eu³⁺ nanoparticles were investigated by energy dispersive X-ray spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM) measurements. XRD studies confirmed that all the samples had a cubic structure with good crystallinity. TEM showed that the particles were polycrystalline with a mean size of 5–8 nm. XPS revealed the oxidation state of the Eu in the ZnS lattice to be +3. All the Eu³⁺ -doped ZnS nanoparticles exhibited room temperature ferromagnetic behavior as a function of doping concentration. The observed RTFM may be interpreted by the contribution of the magnetic moments from the unpaired 4f electrons of Eu³⁺ in the ZnS:Eu³⁺ nanoparticles. The interesting magnetic properties of ZnS:Eu³⁺ nanoparticles may be further explored for new generation spintronic devices.