Cu/Zn/Ce-substituted NiO semiconductor: High ferromagnetic and dielectric properties for technological and energy applications

In this study, room temperature ferromagnetic and dielectric properties of Cu-Zn and Cu-Ce codoped NiO semiconductors have been studied. The coprecipitation route was used to synthesize NiO, Ni_0.95Cu_0.025Zn_0.025O, and Ni_0.95Cu_0.025Ce_0.025O nanocompositions. The X-ray diffraction patterns indicated that all compositions have a pure single phase of NiO with a cubic lattice. The existence of Cu-Zn and Cu-Ce cations in the codoped NiO compositions was verified by energy dispersive X-ray (EDX). The oxidation valence states of Ni, Cu, and Ce ions were identified by X-ray photoelectron analysis as +2, +2 and + 3/+4, respectively. The scanning and transmission electron microscope images of the synthesized powders displayed the formation of nano-sized particles that have high homogeneity. Colossal dielectric constant > 10⁴was detected for Ni_0.95Cu_0.025Zn_0.025O and Ni_0.95Cu_0.025Ce_0.025O specimens at room temperature. A vibrating sample magnetometer (VSM) analysis displayed that NiO, Ni_0.95Cu_0.025Zn_0.025O, and Ni_0.95Cu_0.025Ce_0.025O nanopowders have perfect ferromagnetic hysteresis loops. At room temperature, Ni_0.95Cu_0.025Ce_0.025O composition exhibits the highest saturated magnetization of ∼1.43 emu/g, which is three times higher than the pristine NiO sample. The identified ferromagnetic nature and the colossal dielectric properties of Cu-Zn and Cu-Ce codoped NiO samples make them promising compositions to store data and energy in modern devices.